The Church of the Flying Spaghetti Monster, while having existed in secrecy for hundreds of years, only recently came into the mainstream when this letter was published in May 2005.

http://www.venganza.org/about/open-letter/

With millions, if not thousands, of devout worshippers, the Church of the FSM is widely considered a legitimate religion, even by its opponents – mostly fundamentalist Christians, who have accepted that our God has larger balls than theirs.

Some claim that the church is purely a thought experiment, satire, illustrating that Intelligent Design is not science, but rather a pseudoscience manufactured by Christians to push Creationism into public schools. These people are mistaken. The Church of FSM is real, totally legit, and backed by hard science. Anything that comes across as humor or satire is purely coincidental.