Had a window pop off once. SKW rtb to Culdrose from the northcoast, starboard emergency exit window (held in place by a rubber strip all the way round) decided it didnt like being attached to the airframe anymore. Dropped from 500' in the vicinity of Praze-an-Beeble - never did hear anything else about it. Probably ended up as a mangled souvenir for someone.
1st solo in a 152 on PPL - pilot side door opened whilst rotating - that got my heart pounding even more than it was already !
Oggin