Bill Maher is a political comedian who decides to tackle the current state of world religion. He believes that having faith and seeking guidance from God is ludacris and so, sets off on a one man mission to prove it. He travels far and wide to numerous destinations, such as Jerusalem, the Vatican and Salt Lake City, interviewing Jews, Catholics, Muslims, Christians, Mormons, scientists, gays, and atheists, hoping to prove his point, as well as challenge those who disbelieve the concept of evolution, in this religious, ridiculous, religulous documentary film.