Fun:Effective altruism

Effective Altruism comes complete with:
 * a credo
 * a controversial founder who rejects all other religions and propounds a strict moral code
 * denominations (the three most prominent ones being poverty, animal welfare, and MIRI — although MIRI supporters are theoretically a subdivision of X-risk worriers)
 * sermons, including abstruse technical arguments which may seem pointless to outsiders
 * saints (at least, according to Scott Alexander )
 * breathless evangelists
 * regular meetups
 * an "optional" 10% "or more" tithe, for those who can afford it
 * a tiny, but growing, cadre of full-time functionaries, some paid, some volunteers
 * crazy end-times prophecies (from the MIRI faction)
 * predictions of a wondrous afterlife when this vale of tears is finally over (from the MIRI / nanotechnology / transhumanist / hedonistic imperative factions)
 * … and even a thought experiment about a vengeful god which some people have taken way too seriously.

So, nothing at all like a religion, then!

On the other hand, unlike most religions, effective altruism does entail a commitment to think rationally. Of course, adherents of traditional religions don't think they're being irrational, either…