Volokh Major mentions the judicially-approved 'Shit Happens' bumper sticker (10/24, 3:39 PM if the link doesn't work). A few years ago, I was asked to translate this message into Latin for a summer student I was tutoring to brush up his Latin before he went back to Amherst, Bowdoin, Colby, Dartmouth -- one of those places. He wanted to make a bumper sticker for his favorite professor's pickup truck.

Latin doesn't seem to have a noun exactly corresponding to 'shit'. The verb is easy enough: caco, cacare, cacavi, cacatus is the standard obscene word for intestinal excretion -- and it even sounds like 'caca'. Merda (plural merdae) is close to the right meaning, but it usually means a piece of shit and is therefore more like 'turd'. I went with stercus, which is barnyard language but not obscene: 'dung' or 'manure'. For the verb, I gave him a choice of fit or accidit, leaning towards the latter. Although the meanings overlap, Stercus fit would mean something more like "Shit exists, there is shit in the world", while Stercus accidit could be loosely paraphrased "Into every life some shit must fall". (The basic meaning of accidit is "fall on" and therefore "befall, happen to" or just "occur".) The original English saying is not entirely perspicuous, so a case could be made for either fit or accidit. I don't know which the student chose, or how his professor responded.