That would be the time I had crashed on my brother's couch, and in the morning I heard him sounded very annoyed as he told me to get up, followed by a hefty (and mildly painful) thump on my chest. First instinct was to take a swing at him for hitting me.
About here is where I opened my eyes and realized three things: my left arm was completely without feeling (fell asleep due to the way I was positioned) and it was what hit me in the chest, not my brother. Second, he was at the foot of the couch and nowhere near where I was throwing my punch. Third, the quickness of my movement was effectively launching me out of the couch and towards the wooden coffee table covered in beer bottles & a couple of ash trays, with no possible way of changing course.
So, one loud crash later, with many a broken bottle and one undamaged table, my brother's roommates came running in to see me picking myself up and asking where the broom was, and my brother on the ground laughing his arse off (well, after he saw that I was alright that is).
Also, Honurable mention: Smoke alarm going off after a former roommate caused a bacon fire in the kitchen at 2am. Came running into the hallway in time to see her waving a towel at the smoke detector and hearing her tell me it was out. Was about to give her grief, then I took a tasty sniff at the smoky bacon flavour now all throughout the house and changed my reaction to a big smile as I said 'Nice!' and went back into my room.