| Just a quick survey for anyone interested. The Romans had a typically warped and twisted sense of humor, usually involving one of two things: sex jokes and violence. They preceded A Clockwork Orange by several millenia.
Sex jokes were always about domination. They had no sense of homosexuality and heterosexuality. Rather, the male was sexually dominant, and the female sexually passive; the distinction was between the fucker and the fucked. Thus a male could only take it when he was a youth, before he accepted social and political responsibility (roughly at the age of 31); thereafter, it was a shameful act, and a subject of scandal and ridicule. A prime example is Catullus poem 16, beginning: I'm going to fuck you up the ass (literally, 'treat you like a boy') and shove my dick in your mouth, Aurelius you bitch (thanks, Sylvar, for the suggestions; originally, a pathic: someone who takes it during sex, a passive, a sufferer; any better suggestions for the English?), Furius, you cocksucker...'. Not too far off from modern locker room jokes, there were also quite a few jokes running along the simple lines of 'my dick is bigger than yours...'. This was the basis of poems of Priapus, talking about how your god's statue was going to fuck your enemies if they came too close; Martial has one in which he mocks a woman because she's too sore to fuck anymore, saying she's been using his Priapus as a big stone dildo.
Women who were too sexually active, like prostitutes, were mocked as men, and many of them wore the male toga (as symbols of dominance, but also for easy access; no underwear). Any man who submitted to a woman's desires was called effeminate; cunnilingus was a laughable act for a real man.
Violence also figures prominently; kind of like the modern: "what's black and white and red all over, and can't fit through a revolving door? A nun with a spear through her head". That would be hilarious to any Roman. Martial has a great one about a gladiator being disembowled by a bear. In the same sense, watching Christians being burned alive or crucified wasn't just promoting social stability, but damn funny.
Roman humor reflects an empire fighting wars on all borders, constantly interested in power games. Chastity and submission are only interesting and acceptable once you've become isolationist and peaceful. | 
