It's such a simple formula. Make a hit movie, toss together a lucrative sequel, then ruthlessly milk the franchise until part 7 goes directly to Telemundo. But for every clunker like Leprechaun in the Hood, countless other franchises remain woefully untapped. In recent weeks, Hollywood has been making plans for high-profile sequels -- some we're dying to see, and some make us sad to be a part of the human race. Here, an update on a half-dozen part 2's (and 3's and 4's) in the works:

TERMINATOR, PART 3

Arnold Schwarzenegger announced on June 21 that he'll once again play the monosyllabic time-traveling cyborg, adding that his ''big wish'' is to have T2 director-cowriter James Cameron back. Good luck. Cameron's production company tells EW he will not return, preferring to develop a sequel to another Schwarzenegger vehicle, True Lies. (A Cameron replacement for T3 hasn't been named.) The new Terminator -- which reportedly documents the wars between the humans and the droids -- is slated for a 2002 release, says C-2 Pictures, which owns the rights. PROGNOSIS With Arnold's shrinking box office muscle (see End of Days) and Cameron's absence, filmgoers might just say, ''Hasta la vista, baby.''

INDIANA JONES, PART 4

Throw them the script and they'll throw you the sequel. Since 1989's Indiana Jones and the Last Crusade, Harrison Ford, producer George Lucas, and director Steven Spielberg have all expressed a desire to do a fourth Indy -- but screenplay attempts have been lackluster. Apparently, things are looking up: The Indy team recently approached Sixth Sense writer-director M. Night Shyamalan and various unnamed scribes to tap out part 4. ''As soon as a script gets done, they'll do it,'' confirms Ford's manager. ''That could be 2002.'' Spielberg spokesman Marvin Levy calls that optimistic. ''Steven's got AI, George [has] Star Wars. Do the math. We could be lookin' at 2007, but your guess is as good as mine.'' PROGNOSIS If Ford isn't in a wheelchair by the time they get to this, we'll be first in line.

JURASSIC PARK, PART 3

Seeing as 1997's Lost World stampeded box office records (U.S. total: $229 million), it doesn't take an evolved brain to know this one was inevitable. Jurassic Park III begins shooting later this month or early next in California and Hawaii, with a release target of July 2001. Sam Neill just agreed to reprise his intrepid paleontologist role, and, according to a source close to the film, Laura Dern is in talks to make a cameo. Steven Spielberg, however, is pulling back: He'll most likely executive-produce, with Joe Johnston (Jumanji) replacing him as director. And the plot? A source tells EW a group of unlucky folks will somehow be marooned back on Jurassic Park island and forced to fight their way out. Special-effects wizard Stan Winston is currently cooking up a top secret new dino-star, possibly an underwater monster. PROGNOSIS Pretty much a sure thing. The strong performance of Dinosaur proves dinomania hasn't gone the way of, well, you know.