The Swallows by Lisa Lutz

This book is like a game of Clue but instead of people killing each other off in a mansion it is sexual high jinks, girls against the boys in a boarding school that gets totally out of hand. Alex Witt is a very witty teacher who has left her last teaching position and now takes a job at a New England boarding school to get away from her author parents. She needs this job so she is willing to teach creative writing (which she has never taught), live in an almost inhospitable cabin and admit to herself that by taking a job from an old family friend, she is desperate. She soon finds herself immersed in secret societies, unusual staff and a group of amateur sleuths who are sick of the "boys will be boys" attitude and are willing to do anything to take down the boy's secret club. Intense and unpredictable and wildly entertaining, this is one whodunnit that you will stay up to finish - even on a school night.