Image Credit: Eric Charbonneau/Le Studio/WireimageFor a guy known for being a serious actor, Matt Damon is pretty funny — or at least he seems to be when the room is filled with his longtime pals and colleagues, such as Ben Affleck, Robin Williams, Don Cheadle, Clint Eastwood, Charlize Theron, Greg Kinnear, Casey Affleck, Jennifer Garner, Jimmy Kimmel, and Sarah Silverman.

Last night they all gathered at the Beverly Hilton Hotel in L.A. to honor Damon for his film and philanthropic work. A taped version of the event, “Hollywood Salutes Matt Damon: An American Cinematheque Tribute,” will air in April on ABC.

So, a lifetime achievement award for an actor who hasn’t even turned 40? According to American Cinematheque, who’s been hosting similar events since 1986 to raise money for their cinemas and public programming operations (past recipients include Michael Douglas, Mel Gibson, Tom Cruise, George Clooney and Julia Roberts), it’s more of a “mid-career” award. But that didn’t stop Jimmy Kimmel from lampooning the proceedings in his opening monologue: “They must be running out of stars for awards. Who will we honor next year? Vanessa Hudgens?”

There was definitely a casual vibe at the black-tie affair. The audience (about 700 people, most of whom paid between $500 to $2,200 for a ticket) was light on celebrities, and heavy on industry types, fans, and members of American Cinematheque. Cell phone cameras were clicking constantly. Clint Eastwood, who was seated next to Charlize Theron and Sarah Silverman, got up and down from his chair so much to oblige the line of people wanting to snap a pic with the legend, he probably didn’t have time to finish his salad and salmon entree.

Damon’s table (which included his parents, brother, and wife, along with Ben Affleck and Jennifer Garner) didn’t seem too interested in sitting and eating either, as they stood and chatted happily before the official proceedings. Damon and his wife, Luciana, held hands constantly, while Ben and Jen whispered into each other’s ear, with Garner giving Affleck an affectionate stroke under his chin.

The official ceremony, which only lasted about an hour, consisted of short, scripted “roasts” of Damon and a slew of clips, from Damon’s first role, in 1988’s Mystic Pizza, to this year’s Green Zone. (The reel showed how little his boyish good looks and sandy highlighted hair have changed over the years.) There were so many Jimmy Kimmel moments (including the famous viral video with Sarah Silverman, and the more recent Handsome Men sketch) that at times it seemed more like an ep of Kimmel (and a serious cross-promotion for ABC).

Surprisingly, professional comedians Robin Williams and Sarah Silverman were the most subdued, while the laconic Eastwood (the only presenter who didn’t read from a teleprompter) delivered some of the funniest lines: “Matt Damon is one of the finest actors of our generation. I know that because when he came into my office for Invictus, he said, ‘Clint, I am one of the finest actors of my generation.’ In fact he couldn’t understand why I cast Morgan Freeman as Mandela, he felt he could handle it.”

Casey Affleck, who has known Damon since Casey was 7, got the biggest laugh of the night from the room and Damon himself when he pulled up a slide of a so-called “vacation shot” of the two of them lying around naked, with a very small black bar hiding Damon’s privates and an extremely large one over Affleck’s. (It will be interesting to see if that makes it to the broadcast.)

Of course there were more serious moments. Charlize Theron (who starred with Damon in The Legend of Bagger Vance) paid tribute to the actor’s philanthropic work and introduced a taped message from President Bill Clinton, who thanked Damon for his efforts in Darfur and Haiti, and for his commitment to bringing clean water to those areas.

Another taped message came from Ben Stiller, who has never worked with Damon and aptly prefaced his remarks by saying that this was the reason he couldn’t be bothered to actually show up. A misfired sketch featuring the absent George Clooney dressed in a hospital gown and pretending to be getting a proctology exam while addressing the room was about as excruciating as the actual procedure would be.

It was left, of course, to best pal Ben Affleck to actually present Damon (whom Garner introduced as “my husband’s husband”) with his award, noting dryly: “Wow! A lifetime achievement award? I started the same time as the guy — so it’s a special night for me too. I actually accepted an award recently as well from the Elks Lodge!”

In the end it really proved to be Damon’s night when he took the stage to receive the award and proceeded to dish out all that he gotten over the course of the ceremony. In fact most of it was off the cuff, as he ignored the lines scrolling in front of him on the teleprompter. He thanked Affleck (who he referred to as his hetero lifemate) and assured him that. “Next year I’m sure you will be on this stage (presenting this award to someone else).”

He did perfect impressions of Clinton and Eastwood, saying his award paled in comparison to Eastwood’s lifetime achievement award from AARP. To Silverman, he said: “Well, it was over before it started — and in fact that’s what you told me about Jimmy.” He also wondered aloud why Ben Stiller was even invited to speak (“I guess you heard there was something being made in Hollywood that didn’t have you in it”) and called Clooney’s taped message “strange” (to say the least).

He finished his 12-minute response by thanking his family until he was yanked offstage by Kimmel and his TV sidekick Guillermo, who said Damon had run out of time.

So what’s next for the career achievement recipient? “I don’t know. I guess I go back to work and try and earn the award,” he told EW. –Katherine Tulich