I've mentioned the goliards once or twice already, but I've been saving up an in-depth look, and now's as good a time as any.
Short answer: Half-drunk college students.
Long answer: All-drunk, philandering, slandering, over-educated clergymen who vandalized services and scandalized priests from the Twelfth to the Thirteenth Centuries.
They staged obscene plays in front of cathedrals. They led donkeys in costumes up to the altar rail and disrupted the Mass. They ate their sausage lunches on the altar, mocked the local bishops, and burned old shoes in the incense burners. They wandered from town to town in an age when most people died less than fifty miles from where they were born. They were, in their way, the last gasp of paganism until the Renaissance. They got drunk, got into brawls, and wrote the best Latin poetry in two hundred years. Of course, half of it was drinking songs and the other half was satires of the Church, but still.
The fact that they were both college students and clerics might cause a bit of cognitive dissonance to modern minds. Back then, the Church had something like a data monopoly in Christian Europe. The universities evolved from cathedral schools and monastic schools, and weren't autonomous until the 13th Century. If you wanted to study, the best way to do it was to take vows.
That didn't necessarily mean becoming a priest. In addition to the "major orders" - bishop, priest, and deacon - there were the "minor orders" of acolyte, lector, exorcist and porter. These minor orders didn't demand the same life changes as the major orders, and they had benefits. Like not being tried in a secular court of law, but in a church court, which was much, much cushier.
So there were huge incentives to be a minor-orders guy. And since there were huge incentives, there were a LOT of clergy. One estimate was that one out of every five men in England in the middle of the Twelfth Century had taken vows of some kind.
And what happens when you take well-educated, not particularly celibate, not notably hardworking students and shove them all together in big cities like Paris and Boulogne? Lots of drinking, fights, sex and racy Latin poetry.
To be fair, they were also motivated by the Church's corruption and the failures of the Crusades. And when a single institution spans the entire continent and not only lays claim to your behavior in this life, but your fate in the next, it takes some guts to tell the hierarchy to go shove it. But the goliards did, for a century and half, until the Church finally clamped down on them, hard, about 1300: church councils against them, and the ultimate penalty of defrocking.
Next goliard post: Some more drinking songs! Yay!