From Wikipedia
Penn & Teller (Penn Jillette and Teller) are American illusionists and entertainers who have performed together since the late 1970s, and are known for their numerous stage and television shows. Their current Las Vegas show is an amalgam of illusion and comedy. Penn Jillette is a raconteur; Teller generally does not speak while performing, although his voice can occasionally be heard during their performance. They specialize in gory tricks, exposing frauds, and performing clever pranks. More recently they have become associated with atheism, scientific skepticism, and libertarianism, particularly through their television show Penn & Teller: Bullshit!.