This wasn't really something that was directly my fault, but it was the most aggravating gaming experience I had. I was playing Fable III and had reached the big battle where I storm the castle to overthrow my brother. I was jumping over this stack of sandbags and all of a sudden I was below game-surface suspended in midair and stupid me I pressed "save" before restarting the game and the game opened with me suspended-midair unable to do anything (afterwards I realized the auto-save would've saved the game at that point anyway so nothing I'd have done would've made a difference).
Searching the web I found out this was one of the big glitches in the game, and usually if you invited another player into your game and had the player buy something from a stall or dig something from a digspot, you would get back on track, but being mid-battle there were no digspots or stalls available... I tried and tried again cause seriously, I wasn't about to let all those hours of gameplay go to waste, but nothing I did made any difference. Then amazingly enough a cut-scene was triggered of the wall being blown up and suddenly I was back on game surface with my character and could continue the game. Never been so relieved before in my life.
I also had a screw-up with OoT3DS cause I had played for a while and managed to hit the power-button before saving and I couldn't figure out how to get back to my game to save, luckily I hadn't been playing *that* long, but still... be careful with that power-button :S