Hosted by professional magicians/comedians Penn & Teller. Many episodes aim to debunk what the hosts see as pseudoscientific ideas, supernatural beliefs, popular fads and misconceptions, often from a libertarian point of view, the political philosophy espoused by both Penn and Teller. The show criticizes proponents of what they perceive as nonsense and dishonesty, often citing ulterior political or financial motives. The stated aim of the show is to apply critical thinking to misconceptions, and as is indicated by the show's title, the program adheres to Penn & Teller's characteristically blunt, aggressive presentation.

Supernatural subjects of episodes include alien abduction, alternative medicine, and ESP; other episodes cover social issues such as the War on Drugs, animal rights, gun control, and environmentalism. Penn & Teller approach the topics in the manner of Harry Houdini and James Randi (who has appeared more than once on the show), who are known for debunking claims of supernatural powers.

The on-going show has aired its sixth season in the United States. The series has achieved worldwide success, being shown in countries such as Australia, Bosnia and Herzegovina, Brazil, Canada, Denmark, Mexico, New Zealand, Sweden, Colombia, Finland and the United Kingdom.

• Official Showtime website
• TV.com episode guide
• Bullshit! It's No Bull - Perry DeAngelis' review of the show
• Fridays with Mr. Media: The Star Price/Penn & Teller: Bullshit! Interview by Bob Andelman
• Wikipedia!