Burning Down the House
I really do wish that people would clean up after themselves sometimes. One of my flatmates left the grill pan in the bottom of the oven still have caked with grease. Not realising this and wanting to make some tea I turn the oven on, crank the temperature all the way up and then leave it for five or ten minutes to get up to temperature. I come back, open the oven door and get hit in the face by a cloud of smoke that quickly fills the room thanks to the grease having started to burn. Had to quickly grab it and throw it into the sink and turn the taps on to cool it down.
Thankfully there was nothing damaged. Unfortunately the two Bulgarian girls had about six or seven friends over and were sitting around the kitchen table, listening to music and playing what looked like Monopoly. Queue all enveloping cloud of nasty foul smoke and they had to relocate fairly sharply. Considering how thick the smoke was I'm surprised that the fire alarms didn't get set off.