Well, I was minding my own business drinking with some friends when, in an odd coincidence, one of said friend's sister called and invited us all to a party. Not being terribly great at parties, after a long period of convincing, we attended the party.
At the part, I did what I always do. That is, clutch my booze tightly, lean on a wall, and pour booze into my face until disinterested strangers seem less terrifying. During this crucial process, a girl walked up to me wearing lingerie and fairy wings (it was a Halloween party) and asked for a drink. I stared at my personal bottle of booze, the only liquor on premises (there was beer of course) and thought very long and hard about sharing. Eventually I did.
As the evening wore on, the party shifted to a different location and finally wound down. The girl and I were driven back to the initial friends house I started the evening at, and were pointed toward the futon. I then proceeded to lay down, on a futon, with a largely naked girl right there who, I think was at least a little interested, and went to sleep. The next day, just before she left, I finally decided to ask her out.
Funny thing is that it never actually occurred to me at the time that she may have been wanting to do anything naughty.
A week later I deployed to Iraq and assumed I'd never see her again. Then seven years later, we were coincidentally in the same city so we met for lunch. Now I'm engaged to her.