This weekend Zach Galifianakis stars with Robert Downey Jr. in Due Date, from the director of The Hangover and its upcoming sequel. Critics are already saying the road comedy follows the same territory as most every buddy road picture in existence, but that RDJ and Zach hit it off really well onscreen.

But, save for a few standout quasi-dramatic roles, this is Galifianakis' tenth film as the weirdo, hairy dude with studio-approved ticks and features. He's getting very close to Will Ferrell Land and doesn't seem to be showing any signs of easing off. Remember in 2008 when every Ferrell comedy had four-word titles and all centered on a bumbling asshole with a sweet job?

As with anything else, if the well keeps producing, you keep drilling. Even if it's the same film over and over again. After Due Date, Galifianakis will have the second Hangover in the can, plus a role in Puss In Boots' own Shrek spin-off as the voice of Humpty Dumpty. Will Zach's Humpty have endearing social ticks, keep ants in garbage bags and sport a mild case of Asberger's? Only time will tell.

He's not the only actor who's made their mark flogging a dead horse. The best actors use it to jump off into other strata. Look at Jim Carrey, who stretched his legs with The Truman Show and The Majestic, after things like Dumb & Dumber and two Ace Ventura pictures. Even by his standards, Liar Liar had a touch of drama in it.

Here are the the top 10 actors in desperate need of a stretch.

10. Jason Statham We're waiting for Statham to play a chubby, mentally-challenged garbageman with a heart of gold. You can only shoot so many guns, and that's hard for us to admit.