Hey, have you noticed how the celebrity supply in New York has been depleted these past few days? (Thankfully, we still have Tom Brady wearing a boot in the West Village.) It's because all of the actors and directors are at the Sundance Film Festival in Utah. But it seems like even in the celebrity fustercluck that is Park City right now, planners still can't get enough star power to fuel their events. Apparently, Sundance schedules are so jam-packed with appointments, parties, and swag-suite visits that it's no wonder they don't make half the events they (well, their publicists) say they will.

Of course, some no-shows you can see coming: Robert De Niro and Quentin Tarantino "expected" at a dinner for 50 Cent, sponsored by VitaminWater? Um, sure. And we look forward to seeing Paris at the poetry reading.

But a lot of high-profile guests this year have opted out of events you'd think they would have at least dropped by. Glamour magazine's "Reel Moments" program helped Kirsten Dunst realize her directorial dreams with the short film Welcome. But when the magazine threw a party for her Sunday night, she didn't show. (Cast members of A&E's Paranormal State held a midnight séance, but failed to call forth an explanation.) Similarly, Ben Affleck skipped out on a Variety party honoring him for his most recent film, Gone Baby Gone. Wonder if anyone appreciated the irony there?

U2 was slated to perform at Greenhouse following the premiere of their much-hyped film U2 3D, but instead they hung out upstairs receiving celebrity visitors. While many esteemed and award-winning actors submitted themselves to endless interviews and photo shoots on Sunday, Entourage star Adrian Grenier skipped out. Sienna Miller, who was expected to be in town promoting Mysteries of Pittsburgh, deferred last-minute. And Velvet Revolver front man Scott Weiland was in absentia during his band's performance Sunday night, supposedly because he missed his flight. This was an unforgivable offense, as it enabled an already overexposed Paris Hilton literally to take the stage. (She didn't sing, but she did try to play drums.) But isn't that what sets Paris apart? You can at least count on her to turn up — and risk getting pegged with snowballs. —Darrell Hartman