As the old Joni Mitchell song goes, Judd Apatow has looked at life from both sides now. Before tasting the thrill of victory — as the producer of hit comedies like Anchorman and Talladega Nights and the director of 2005's The 40 Year-Old Virgin and this summer's Knocked Up — he experienced the agony of defeat as the creator of such brilliant-but-cancelled TV series as The Ben Stiller Show, Freaks and Geeks, and Undeclared. Victory, it's safe to say, is a lot more fun. With the latest film from the white-hot Apatow laugh factory, the raunchy high school comedy Superbad, opening Aug. 17, we brought together Apatow (the film's producer), Seth Rogen (its cowriter and costar), and the film's two leads, Jonah Hill and Michael Cera, for a rollicking and very R-rated conversation about the ins and outs of comedy — the supergood, the superbad, and the superugly.

In the third of three installments (if you missed them, follow these links to part 1 and part 2), the comedians discuss the inspirational George Clooney, The Mighty Boosh, and how even babies can improvise. (And, yet again, be warned: When we say this roundtable chat is R-rated, we mean it.)

ENTERTAINMENT WEEKLY: The process on these movies seems very different from a show like Arrested Development, where actors stuck closely to the words.
MICHAEL CERA: Well, [Arrested Development had] very meticulously written jokes, but it wasn't very strict. You could say whatever you want after you did the first take.
SETH ROGEN: Often, time just dictates that. You just don't have a whole day to shoot one scene. That's what's nice about a movie.
JUDD APATOW: We have way too much time. Larry Sanders, they shot the show in two days, 17 pages a day. Shoot a scene in an hour, shoot another scene in an hour. There wasn't much time to play around.

You guys do a huge amount of improvising in these movies. Is that hard for some actors to get used to?
APATOW: Most people who are funny can improvise if they relax and allow themselves to think they can. The ratio of success can be very low and it can still be very helpful to the movie. Katherine Heigl never thought she could improvise and she was fantastic at it. She left the audition thinking she didn't get it, and we were like, ''Oh my God, that was awesome.'' So it's hard to tell.
ROGEN: I've never met anyone that we've worked with who just can't do it. Especially the way we work. All our scenes are based in reality and conversational. I always said to Katherine Heigl, ''It's not like I'll be like, 'So where should we go for dinner?' And you'll just be like, 'Uh, uh...I don't know!'''
APATOW: ''There's no dinner in the script!'' [Laughs]
ROGEN: If you can listen to the question, you can probably do it.

But to come up with something funny and also move the scene where it needs to go —
APATOW: Well, we always talk about it before it happens and we'll throw people lines or ideas or areas. People aren't really just hanging out there on the line.
JONAH HILL: I think a lot of it is being so scared not to do it, you just do it. If someone put you in that position and there's cameras around and you didn't do it, you'd feel so s----y.
APATOW: My 9-year-old daughter did it on the first day. That's what I'm going to say on the rest of my movies if an actor can't improvise: ''My f---ing 3-year-old did it! She could improvise with a s--- in her pants!''
HILL: What is being really funny if you can't improvise and create your own kind of thing?
APATOW: There are people who are just interpreters. David Mamet doesn't want you to improvise.
ROGEN: And that's why he's so funny. [Laughs]

Not every comedy director would be so open to improvising. I don't know that Woody Allen loves a lot of ad-libbing on his set.
APATOW: He will let you change a line — at least that's what they say. I don't know if anyone has the courage to do it, but I think the invitation is there.
ROGEN: I would. It would be so funny if I worked on a Woody Allen movie and I didn't say one thing he wrote. ''Thanks for the suggestions.''
APATOW: You're three months away from being in a Woody Allen movie, by the way.
HILL: As you said that, I was thinking, Jew in New York, starring Seth Rogen.'' I guarantee Seth will be in a Woody Allen movie. But you'll be in one of the serious crime-thriller Woody Allen movies. You're going to kill Scarlett Johansson.
ROGEN: Match Point 2: The Rogening.

NEXT PAGE: ''You can't really fight over the specific syntax and language of a d--- joke. You can't be that proud of it.''

ENTERTAINMENT WEEKLY: Michael, was it intimidating for you to come in and have to work that way, with so much improv?
MICHAEL CERA: Definitely. But we did rehearsals for a month beforehand where we'd hang out at Seth's house and we did a bunch of table reads. I felt like I knew it really well, and we were so comfortable around each other.
SETH ROGEN: We set a precedent pretty early. One of the first things we did when they were all cast was we had them over to my apartment and we went through the script line by line and just said, ''How would you say this line? What would you say there?'' We made it clear, ''We don't give a s---. Say whatever the hell you want.'' Why hire Michael Cera if you're not going to let him do that s---?
JUDD APATOW: You can't really fight over the specific syntax and language of a d--- joke. You can't be that proud of it.

Obviously, the advantage of having people improvise is that it gives you things you can't come up with in advance. But at the same time, doesn't it make it harder to cut the film together at the end?
APATOW: That's why I wanted Greg to direct Superbad. He's just a fantastic writer, and I knew in the final polish stages of the script, he would make sure the emotional aspects of the movie worked really well and he would find that balance. That's why he so outclasses us in his abilities. He took something that could have been very base and awful and made it...I mean, it's funny and filthy but it's also a beautiful movie about friendship and people cry at the end of the movie when these guys have to part. It gets me every time.
JONAH HILL: What always pisses me off is when you'll hear, like, five dudes laughing at the ending. It makes them too uncomfortable, so they go ''huh-huh.''
CERA: It's too real.
APATOW: ''Feelings! Emotions! Must shut them down! Punch someone!'' Well, the movie always was about guys who are afraid of intimacy covering it up with this incredible bravado and talking about what they're going to do to women, and it's all bulls---.
ROGEN: The joke to me and Evan was always, like, in the first five minutes of the movie they could have walked up to these women and asked them on dates and the movie would have ended right there. The whole movie takes place as an excuse for them not to actually talk to these girls.
APATOW: Because there is nothing scarier than that. I've never walked up to a girl in a bar once in my entire life. I've never had the courage to see someone and talk to them. So I always relate to that story.

Are there clichés or setups in studio comedies that you feel like are just so played out, you can't stand them anymore?
ROGEN: I like it all. If Knocked Up taught us anything, it's that you can take an idea that's very sitcomy and clichéd and if you approach it from an original standpoint it won't be.

I have to say, the logline on Superbad: two geeky guys trying to buy beer —
HILL: It sounds like the worst movie ever.
ROGEN: It doesn't just sound like the worst movie. It sounds like a million other movies.
HILL: Seth and I were talking about making a grindhouse double-feature: Boner Party and Boobie School. [Laughs]

NEXT PAGE: ''I remember being booed off the stage at UC Santa Barbara. I was opening up for Marc ''Skippy'' Price from Family Ties. I was terrible. I had a lot of jokes about condoms.''

ENTERTAINMENT WEEKLY: Judd, you've developed this sort of repertory company of actors and cowriters who are significantly younger than you. There's a 20-year age difference between you and Michael here.
JUDD APATOW: Jesus Christ, this just took a very dark turn. You son of a bitch. And thus began the beginning of my creative paralysis. [Laughs] It's true, though, I could be Michael Cera's dad. I could be everyone's dad here if I started having sex at 14.

From the outside, it seems unusual that you guys manage to work so well together and have such similar sensibilities.
SETH ROGEN: It's funny, when I met Judd and learned about all the stuff he did, I realized that's the stuff that directly influenced me. I mean, like, Adam Sandler's comedy albums were gold to me. Those were the first things that made me think, S---, there are things you can do with comedy I never thought you could. And Judd helped out with those.
APATOW: Very little.
ROGEN: And The Ben Stiller Show and Larry Sanders. All those things were huge.
JONAH HILL: That's how I found out who Judd was. I kind of compiled a bunch of s--- that I liked and his name was in the group of that the most.
ROGEN: You did a Bible-code-type thing.
HILL: I did a Beautiful Mind. But that's how I figured it out, because I kept seeing his name on s--- I thought was cool. [To Apatow] How does that make you feel, dude?
ROGEN: You're responsible for this filth.
APATOW: I feel so old right now. My wife was watching the trailer for Superbad and it says, ''From the guy who brought you 40 Year-Old Virgin and Knocked Up,'' and she just turned to me and went, ''Great, now you've become that guy.'' [Laughs]

Judd, it must surprise you to find a guy like Michael, whose sense of comedy is so highly developed at age 19.
APATOW: I am surprised because I was so unfunny at that age. I mean, I was really not funny at all at 16, 17, 18, 19. I look back at old standup tapes and notebooks and it was really godawful and embarrassing. So yeah, to see guys who really know what they're doing and are sophisticated, it makes me ashamed of everything I did in those years. I think back to being around all those comics I admired, having them see my act and how bad it was — that's brutal. I remember being booed off the stage at UC Santa Barbara. I was opening up for Marc ''Skippy'' Price from Family Ties. I was terrible. I had a lot of jokes about condoms: ''My grandfather gave me a condom. It was made out of wicker.'' That was about the level of the act. It wasn't really at the Arrested Development level.

NEXT PAGE: ''Look at Mel Brooks. He's having hits at 80. He's doing Young Frankenstein on Broadway. It's possible next year won't suck.''

ENTERTAINMENT WEEKLY: Michael, does that mean you're sitting around feeling self-conscious about how much older these guys are than you?
JONAH HILL: Well, we molest Michael. It's a different vibe.
SETH ROGEN: We were saying, if Michael's career doesn't go well, he could be the kid on To Catch a Predator.
MICHAEL CERA: [In high, boyish voice] ''Did you bring the vodka? I'm going to get changed. I just got out the shower. I'm drying my hair. Sit down, there's some cookies over there.''

Where do you guys go for comedy? Jonah and Michael, I know you two are big Zach Galifianakis fans.
ROGEN: He's hilarious. I love Extras. The Office.
CERA: There's a [British] show called Garth Marenghi's Dark Place. That's the most brilliant show.
HILL: I love Edgar Wright's movies. The Mighty Boosh on the BBC is really funny.

So with the winning streak you've been on, where do you go from here? Do you think it can continue or do you have a sense of doom?
JUDD APATOW: I'm always trying to think of people who've had careers that have lasted more than four months. That's how I'm choosing to get through this. Like, okay, these people have made some decent movies over a 10- to 25-year period. It wasn't just a little summer. Look at Larry Gelbart. Look at Carl Reiner. Look at Mel Brooks. He's having hits at 80. He's doing Young Frankenstein on Broadway. It's possible next year won't suck. [Laughs]
ROGEN: I've had some good luck, so I'm always thinking something terrible is going to happen. But then I'm like, Look at George Clooney. He's done way more movies than us — and he's really handsome. Nothing terrible's happened to him. It just keeps getting better and better.
APATOW: The postscript to this is: ''Judd nibbled some dog food made in China and dropped dead on the spot.''
ROGEN: ''Oddly, a meteor hit the table, killing Michael, Seth, Judd, and Jonah. Josh and his tape recorder were completely unscathed.''
HILL: I'll bet you $1,000 that's how this interview ends.