Didn't happen to me but I always think about this when you talk embarrassing moments.
Working at Chuck E Cheese one day there was a lesbian couple making out, and I mean really making out. Many parents came to my boss and complained. "This is a family establishment...blah blah." So after the fifth complaint my boss went over.
"Ladies, this isn't the place for that type of behavior." (he would have been fine..almost if he had stopped there) "This is a family establishment and some people just aren't comfortable with same sex PDA."
To which one of the women stood up and shouted, "I AM A MAN! HOW DARE YOU CALL ME A WOMAN!"
Yep, it was a guy, none of us could believe it. My boss just stammered...sorry and basically ran away. Later I heard a co-worker laughing at him and say, "I didn't know a guy as dark as you could turn so red."
ADDED: I just thought of one. One day I was at work talking to a guy named Jeremy. The phone rang and I answered, " Thanks for calling Commercial Federal this is Jeremy...wait no it's not." Jeremy was laughing his butt off.
I also had a co-worker talking to a woman about her daughter. The woman told my co-worker that the ATM only gave her daughter 30 instead of the 40 she requested. This was impossible because the ATM only dispensed twenties. So my co-worker says, "I think she is trying to pull the wool over your eyes." The woman was blind.