I'll start with mine...it was a bitterly cold January morning about 4 years ago and I was getting up early to meet with a builder on a construction site before office hours. I got dressed in the dark (didn't want to wake my girlfriend up) and grabbed my winter jacket (w/ velcro hood attachment) out of the dryer on my way out the door.
When I arrived at the site, I noticed the builder kept grinning but I couldn't figure out what was sooo damn funny. Finally I got back to work and my boss started laughing. I said "what is soooo damn funny?" and he told me I had something on my back. Turns out I'd been walking around all morning with a pair of my girlfriend's panties stuck to the velcro on my jacket!