Benjamin Edward "Ben" Stiller is an American comedian, actor, writer, film director, and producer. He is the son of veteran comedians and actors Jerry Stiller and Anne Meara. After beginning his acting career with a play, Stiller wrote several mockumentaries, and was offered two of his own shows, both entitled The Ben Stiller Show. He began acting in films, and had his directorial debut with Reality Bites...(wikipedia)

Zacharius Knight "Zach" Galifianakis is an American stand-up comedian and actor, known for his numerous film and television appearances including his own Comedy Central Presents special. While initially more of an "underground" comedian, he has garnered mainstream attention for his role in the Todd Phillips-directed comedy film The Hangover... - www.wikipedia.org