Bill Maher's take on the current state of world religion, with the title being a play on the word 'Ridiculous' mixed with 'Religion'. Maher and his siblings were brought up as Catholic's, due to their father being a Catholic, but with their mother remaining a practicing Jew throughout their childhood. The Maher family moved away from their beliefs in latter years, as we hear from them during this entertaining film. During Religulous, Maher questions staunch members of all faiths, and in the process, he reveals plenty of ridiculousness within all of their teachings.