Nothing near as bad as a corrupt saved game of hours upon hours but: I was playing Halo on the Xbox, fighting my way towards the end. There's a part where you had to fight your way out of some stronghold with a bunch of funky crab creatures (?-it's been years since I played it so my memory is a bit rusty). Anyway, there's a part where you drive a warthog to do some sort of daring escape and at that point the game froze. I had to hard reset and I got back to the last save point, but the segment was grueling and a pain in the butt I decided not to try again that night. Nor have I played it since.