Warning: we may be losing the best actors of our generation.

Joseph Gordon-Levitt is at Sundance -- partly to talk up the premiere of "Hesher," but also -- and he seems more pumped about -- pushing his nebulously-defined production company hitRECord.org, a multi-media film/interactive/music/god-knows-what that will have a presentation in Sundance's newly-minted New Frontiers division. Now, more power to him, but this certainly isn't where I thought his career would be five years ago. That's when he gave two superlative knockout performances back-to-back -- in "Mysterious Skin" and "Brick" -- before getting bogged down in a bunch of movies that unexpectedly went south: "Havoc" (directed by Barbara Kopple, written by "Traffic"'s Stephen Gaghan, but somehow most notable for Anne Hathaway's topless bits), the stillborn, DTV Elmore Leonard adaptation "Killshot," "Miracle at St. Anna," etc. All were promising projects that unexpectedly caved. He had a hit with "(500) Days Of Summer" and a paycheck with "G.I. Joe: The Rise of the Cobra";...

Joseph Gordon-Levitt is at Sundance — partly to talk up the premiere of “Hesher,” but also — and he seems more pumped about — pushing his nebulously-defined production company hitRECord.org, a multi-media film/interactive/music/god-knows-what that will have a presentation in Sundance’s newly-minted New Frontiers division.

Now, more power to him, but this certainly isn’t where I thought his career would be five years ago. That’s when he gave two superlative knockout performances back-to-back — in “Mysterious Skin” and “Brick” — before getting bogged down in a bunch of movies that unexpectedly went south: “Havoc” (directed by Barbara Kopple, written by “Traffic”‘s Stephen Gaghan, but somehow most notable for Anne Hathaway’s topless bits), the stillborn, DTV Elmore Leonard adaptation “Killshot,” “Miracle at St. Anna,” etc. All were promising projects that unexpectedly caved. He had a hit with “(500) Days Of Summer” and a paycheck with “G.I. Joe: The Rise of the Cobra”; he’s got a part in “Inception” coming up. It’s not like he’s stopped working out of discouragement.

But when he starts turning into a whirlwind of enthusiasm over something that isn’t acting, you have to wonder how long his interest for his first career will last. He wouldn’t be the first actor of his generation to admit they’re not that interested. Ryan Gosling has a movie at Sundance too (“Blue Valentine”), but he’s made it clear acting is no longer his primary interest; that would be his band Dead Man’s Bones. “I made a couple movies because I had to, but this is all we do,” he said.

His contemporary Michael Pitt has slowed down as well, preferring to focus on his band Pagoda. And who knows how long James Franco will put up with the lack of appropriate comic parts for him? That’s something his upcoming role in, say, “Eat, Pray, Love” is unlikely to solve, and he’s way into his painting and performance art (not to mention his SXSW-premiering documentary about “Saturday Night Live”), making it easier for him to just drop out.

All these guys are roughly the same age (birth years ranging from 1978-81), talented and struggling to find parts that are interesting and challenging enough to hold their full attention. They’re way too young to pull the whole Brando “acting just isn’t enough of a challenge anymore.” So they’re all channeling at least some of their energies elsewhere, and who can blame them? I just worry they’ll all turn into Owen Wilson and take the first CGI-talking-animal paycheck they can so they can get back to what they really care about if the interesting parts continue to be sparse.

[Photos: "Hesher," Handsomecharlie Films et al., 2010; "General Hospital," ABC, 2009.]