It's Snowtime: Fun, Flurries & Film at Sundance!

Putting her recent troubles behind her, Mischa Barton is on snow patrol at Sundance as she lobs a slushy snowball at Reece Thompson, her costar in the comedy Assassination of a High School President.

Castmates Tom Arnold and newlywed Jimmy Fallon get cheeky with a hands-on greeting at Thursday's premiere of The Year of Getting to Know Us.

Matthew Perry and Lauren Graham cozy up for a portrait to promote their upcoming dramedy Birds of America, which also stars Hilary Swank.

Freestyling down the slopes Wednesday, snowboarder Woody Harrelson shows off his fancy footwork. His new film, Sleepwalking, debuted at the festival on Tuesday.

Meanwhile, Harrelson's Sleepwalking costars Nick Stahl and the cigar lovin' Dennis Hopper stick together on more solid ground on Wednesday.

Fully equipped for the winter weather, Adrian Grenier tests his superstar snowboarding moves Monday at the French Connection on the Slopes event.

Never mind the slush and cold – the puffy coat-clad cast of the drama Raisin in the Sun – Sanaa Lathan, Audra McDonald, Phylicia Rashad, John Stamos and Sean "Diddy" Combs – huddle up outside Tuesday. Their film will air on ABC on Feb. 25.

At the Sunday premiere of Smart People, Matthew Broderick and a radiant Sarah Jessica Parker, who appears in the romantic comedy opposite Dennis Quaid (not pictured), share a laugh – and seats in the Eccles Theatre.

With hot beverages in their gloved hands, William H. Macy and Felicity Huffman stroll around town Tuesday. Macy is at Sundance to promote his comedy The Deal, while Huffman is supporting her role in the drama Phoebe in Wonderland.

It's family time at the afterparty for The Great Buck Howard at Pierpont Place on Friday, where Tom Hanks faces off with son Colin. The two men play father and son in the film about a tyrannical entertainer (John Malkovich, not pictured) on the fringes of show business.

A pregnant Jessica Alba keeps her bump bundled up Sunday while exploring the Lift – home to the famous gifting suites, where she picked up baby booties! – with fiancé Cash Warren. Warren co-produced the festival documentary Made in America about gang violence (starring Forest Whitaker).

A well-heeled Charlize Theron battles the snowy streets Tuesday at Sundance. The actress – who stars in the festival film Sleepwalking – hit Park City with longtime beau Stuart Townsend.

At the Friday night afterparty for The Wackness – a drama about a teen drug dealer who pays her therapist with marijuana – the film's stars Mary-Kate Olsen and Aaron Yoo reunite on the dance floor.

Giving a shout out to, well, herself, a T-shirt-clad Paris Hilton and a friend rock a game of Guitar Hero III at The Lift on Sunday.

With her writer-producer husband looking on, an animated Brittany Murphy gives the Nintendo Wii a high-heeled workout Tuesday in the Kevin Mazur Celebrity Portrait Studio presented by Nintendo.

Show him the money! Nick Cannon juggles hundred dollar bills and swag from Wii on Friday in the Kevin Mazur Celebrity Portrait Studio presented by Nintendo.

One of the hottest tickets in town on Saturday night? Joining U2 – Adam Clayton, Larry Mullen, Bono and The Edge – for the premiere of U2 3D, their new film showing a three-dimensional view of their 2006 Vertigo tour.

Jack Black (with his Be Kind Rewind costar Melonie Diaz) puts a Sundance twist on the traditional American Gothic pose with shovels and a sexy six-pack on Saturday.