The other day I went to a talk by Dan Dennett, the originator of the idea of universal acid. On a tangent, he mentioned this factoid, which perhaps most of you know about but I did not - the origin of the Jesus fish is a Greek acronym, ICHTHYS, the ancient Greek word for fish. Apparently this stands for Iesous Christos Theou Y(u)ios Soter, or Jesus Christ Son of God Savior. (See here for how it looks with Greek letters. The acronym makes more sense if you remember that CH and TH are single letters in Greek.) So early Christians used to draw a fish with the Greek letters ICHTHYS written inside, and this apparently got translated into drawing a fish with JESUS written inside.
You also probably know about the Darwinian takeoff on the Jesus fish, where the fish has the name DARWIN instead of JESUS written inside. So Dennett came up with his own (Latin) acronym to indicate what DARWIN means:
Delere Auctorem Rerum Ut Universum Infinitum Noscere (Destroy the author of things in order to understand the infinite universe).
I thought it was pretty clever.