Last fall, on a sunny Saturday afternoon in New York City's Lower East Side, Ivan and Ada are quite literally two kids in a candy store. They rush around the aisles, deciding the best way to spend their couple of dollars. Ivan, 13, ends up with two Pez dispensers. His 11-year-old sister Ada buys three Twizzlers that are each almost three feet long. With their sweets paid for, they head out the door.

''Ready?'' asks their mother, who's been waiting outside. ''We've got a show to play.''

Indeed they do. In fact, they've played three this week, and will be playing three more in Austin for the South by Southwest music conference. Ivan (guitar and vocals) and Ada (bass, keyboards and vocals) are Tiny Masters of Today. When Russell Simins from manic rockers the Blues Explosion heard their first single, he got in touch and offered to be their drummer. In September, the Masters released their debut album, Bang Bang Boom Cake, which includes guest appearances from the Moldy Peaches's Kimya Dawson, Karen O from the Yeah Yeah Yeahs, and Fred Schneider of the B-52's. And David Bowie is on record as describing them as a cross between New York '70s noise duo Suicide and so-bad-they're-great cult sister group the Shaggs. He concluded by calling them ''genius.''

''I thought that was amazing that David would even consider writing about us, or even think about us,'' says Ivan, crunching on some Pez and sweeping his long hair out of his eyes as we stand on the pavement outside Piano's, the small club where they'll be playing this afternoon.

You call him David?

''Oh yeah, he's my buddy,'' he says, with sarcasm in his voice and a cheeky half-grin on his face. ''I call him Davey or Davo. He comes around to our place after school.''

How did you feel about the article in Newsweek that called you the future of rock and roll?

''That was a bit embarrassing,'' says Ada, chewing on a Twizzler. ''My teacher put that and some other articles up on the wall of the classroom, and people would look at them and go 'That's you!'''

The duo is called away to do a quick photo shoot across the road with a Spanish rock magazine. While the two stand against a wall, looking as nonchalant as a couple of pint-sized rock-stars-in-waiting can look, their parents — who are both in their forties and prefer not to use their surnames for privacy — talk about their offspring's recent rise to fame. David works at a technology company that deals with music royalties, while his wife Nancy works in children's book publishing. They live in Brooklyn.

''We used to live not far from here on Avenue A,'' says Nancy. ''That's where Ivan and Ada were born. But back then guys in business suits would get out of taxis, buy heroin and shoot up. It was pretty horrible.''

They don't let the kids have a PlayStation or watch TV on school nights, so playing music came about ''as an attempt at good parenting'' and so they could do more with their leisure time.

''We get that thing a lot where people say 'Oh their parents must be pushing them into this','' says David, who used to drum in amateur punk and garage bands in his twenties. ''But believe me, if we were doing that, we'd want them to rehearse a lot more than they do.'' He's also aware that there's a certain novelty value to what they do. ''They'll have to decide eventually if they want to do this seriously or not, but that's up to them,'' he says. ''Right now, people are going, 'Oh, they're kids, they're kind of inept, but that's cool because it's charming.' They've got a get-out-of-jail-free card for a while.''

The kids come back from getting their photo taken, and Ivan falls into the arms of his mother, a sulky look on his face. He's picked up some flu bug, and he's not feeling well. But it's show time in ten minutes.

Inside, David does some last minute technical adjustments with the amplifiers. Russell Simins, a burly guy with a scruffy beard and sunglasses, takes to the drum stool, and then the kids count in the first song. Ivan's guitar sound is gnarly and distorted, alternating between Ramones-style power chords and feedback-laden lead. Ada either plays a big sparkly bass that dwarfs her skinny frame, or stands still and sings, occasionally brushing a lock of hair behind her ear.

Their songs include ''Stickin' It To The Man,'' ''Radio Riot,'' and ''Bushy,'' a song Ada wrote when she was nine, about how kids don't like George W. Bush. They close with a rousing cover of House of Pain's 1992 hip-hop hit ''Jump Around,'' with Ivan performing the rap and Ada providing the siren sounds vocally.

Afterwards they walk through the crowd, shaking people's hands and handing them free stickers and temporary tattoos featuring the band's logo, a skull and two crossed swords. But after 15 minutes it's time to go. Ivan has two bar mitzvahs to attend this afternoon. One of them is for a friend called Matt.

''Oh, tell him about the metal song Matt wrote!'' says Ada.

''Oh yeah!'' says Ivan, perking up. ''It's called 'Fart in a Blanket.' It's so great.''

And with that, Tiny Masters of Today leave the building, their parents lugging guitars and a box of CDs behind them. Genius.