I actually thought of one, happened while LG was down too (5-6 weeks ago).

My room is situated right next to the bathroom, and we've got this massive bath (like a Spa) in it. Anyways, it was raining so didn't much feel like heating up the spa outside, so I turned it on and went back in to my room and hopped on to the computer. Completely forgot about it, until I turned around and realized water was pooling under my door (top floor is on a slant so if its reaching my room it's 10x worse the other side of the house). I'de left it running for about 45 minutes. Anyways, it was going downstairs, leaking through the roof (all the lights on the bottom floor had water dripping heavily from them). Quite the damage bill, luckily we're insured.