If you thought corporate thrillers The Insider and Michael Clayton needed an injection of offbeat comedy, I've got a movie for you.

If you thought corporate thrillers The Insider and Michael Clayton needed an injection of offbeat comedy, I've got a movie for you.

The Informant marks a semi-mainstream return for Steven Soderbergh after a four-and-a-half-hour biopic (Che) and an experimental drama starring an actual porn star (The Girlfriend Experience) - though he hasn't fully returned to Ocean's Eleven crowd-pleaser mode.

Mark Whitacre (Matt Damon under 30 pounds of extra weight, bad glasses and an awesome moustache) is a biochemist-turned-corporate exec at agri-business behemoth Archer Daniels Midland. When the FBI begins investigating his company, Whitacre turns whistleblower, a role he relishes with a nerdy James Bond glee.

Whitacre's tale turns so ridiculous that even a heavily disclaimered "based on true events" at the film's open leads to head-scratching. Subjecting us to Whitacre's bizarrely funny internal dialogue doesn't help. It devolves into an offbeat portrait of a mind that's gone askew.

The movie at large suffers a bit from Soderbergh's occasional tendency to be self-indulgent at the audience's expense, particularly beating the internal voiceover device beyond its usefulness. Still, Damon's performance is a sight to behold, among the year's funniest, and there are more than a few truly funny folks in support (including 30 Rock and Arrested Development vets).

The Informant will probably find an audience that loves it. The laughs are certainly there and build throughout the movie, and there's a real shortage of humor in movies aimed at grown-ups. Still, it sometimes feels as bipolar as its lead character.