I, Sirius Black, Formally Declare War on the Poltergeist

In 1971, Rolls Royce went bankrupt, the British postal workers went on strike, and Sean Connery appeared in his final James Bond film. Unbeknownst to the muggle world (and a good part of the magical community, for that matter), 1971 was also the year that the Hogwarts student body formally declared war on Peeves.

Ironically, James Potter and Sirius Black had surprisingly little to do with it.

Eleven new Gryffindors means eleven new kinds of shenanigans. Wish your luck to Professor McGonagall.