For the 30th anniversary of the Sundance Film Festival, Robert Redford wanted to jump out of a cake. Before introducing the Jan. 16 opening night film, Damien Chazelle's "Whiplash" (which Sony Pictures Classics acquired), Redford revealed to the Eccles Theater audience how he would have liked to celebrate the 30th year of his fest.

"I thought, 'How about we roll a big cake onto the stage and I jump out!?'" Redford joked. "But that got shut down."

Fest director John Cooper followed Redford and clarified that he "did not veto the cake."

PHOTOS: Inside the Parties at the Sundance Film Festival

After the premiere, writer-director Damien Chazelle and stars Miles Teller and Paul Reiser celebrated at an intimate cocktail event at Spur on Main Street. "It's about jazz. It's about music school. It's about drumming," Chazelle said. "It's not a easy thing to say I want to make a movie about a guy who wants to be a really great jazz drummer."

Cooper got teary-eyed later in the evening at the fifth annual "An Artist at the Table" Sundance benefit held at the Stein Erikson Lodge in Deer Valley. Sundance donors and board members as well as artists participating in the fest including Aaron Paul, Mark Ruffalo and Roger Ross Williams attended the 320-person dinner.

"People may wonder why I keep coming back (after 25 years of working at Sundance)," Cooper said. "Ironically it's because of one of the most silent things I do at this very noisy festival. And that is standing backstage with a first-time director in the dark (waiting for their film to premiere) and we both know that their life is about to change. That's what brings me back every year."

Celebrating the premiere of "Hellion," pic's star Aaron Paul called Sundance "bad ass." As for the sweeping success "Breaking Bad" experienced less than a week ago at the Golden Globes, Paul labeled the kudofest "incredible."

"It was a long, beautiful night," Paul said. "I'm so happy that we were all able to celebrate that night together."

On Jan. 17 Slamdance celebrated their 20th anniversary in a heated garage turned club at the Lodges in Deer Valley.

Filmmakers including Bill Plympton ("Cheatin'"), Chris Furbee ("Huntington's Dance) and Thomas Morgan's ("Waiting for Mamu") celebrated fest's first two decades.

Morgan Spurlock, who served as an exec producer alongside Susan Sarandon on "Waiting for Mamu," explained why Slamdance, launched as an alternative to Sundance, was a good fit for the doc about CNN hero Pushpa Basnet (Mamu).

"Being in Park City where all the buyers are and where people are looking for movies is always more important than anything else, so when Thomas asked me what I thought about Slamdance, I said, 'Of course! We have to go!'" Spurlock explained. "Slamdance has proven that they aren't going anywhere. They have earned their respect."

The main drag in Park City hosted plenty other premiere parties over the weekend, including the Grey Goose-sponsored events for Zach Braff's "Wish I Was Here" and Lynn Shelton's "Laggies," where stars Keira Knightley, Chloe Grace Moretz and Sam Rockwell stayed tucked away in a private dinner party upstairs.

Down the street at the Udis-sponsored venue, "God's Pocket" stars Philip Seymour Hoffman and Christina Hendricks toasted their premiere, as did "Happy Christmas" actress Anna Kendrick, who requested dance-worthy jams for later in the evening on Sunday.

At the Participant party on Jan. 17, cohost Joseph Gordon-Levitt performed while party goers at SLS' The Sayers club including Christina Hendricks and Emile Hirsch caught Capital Cities' packed show. Shailene Woodley and Joe Manganiello hit perennial hotspot Tao where guests danced until the club closed at 4 a.m.

UTA hosted its annual gathering at the Riverhorse on Main, with stars John Lithgow and Elizabeth Banks, while Aaron Paul hit the dance floor.

PHOTOS: Inside the Parties at the Sundance Film Festival

Rob Reiner and "The Case Against 8" co-directors Ben Cotner and Ryan White celebrated the premiere of the HBO doc at Wahso on Main St. on Jan. 18. Approximately 15 gay and lesbian couples and their families joined them to celebrate marriage equality. Newly married couples cut wedding cakes while Prop 8 case lawyers David Boies and Ted Olsen lead a champagne toast.