Although one might guess their shared hotness would be the common denominator between these two studs, the friendship between Brad Pitt and George Clooney (pictured at the Venice Film Festival on Aug. 27, 2008) is way more than skin deep. The Oceans 11 costars share a passion for philanthropy -- the two helped co-found Not On Our Watch, a non-profit aimed at putting an end to mass atrocities around the world -- as well as an appreciation for a good joke. In 2004, Pitt told Entertainment Weekly "we have good fun together," while Clooney deadpanned that there was friction when they first became pals. "It was really hard. A lot of ego."