Here's a real embarrassing one I'll confess to.
At my old job, I had a drawer where I kept personal items such as feminine supplies, makeup, a hairbrush, bandaids, etc. One day I needed some feminine supplies so I opened the drawer to pull some out just as the director was coming to my desk. I quickly stuck them in an interoffice envelope and tended to whatever he needed. I went to lunch, completely forgetting about the interoffice envelope full of tampons.

Of course as luck would have it, the mail guy came around and just that moment and delivered the tampons to my boss (whose name was last written on the envelope), a single guy with a Peter Pan complex....hardly the kind of person you'd want to send tampons to. He came out of the office all perplexed and said he got a weird thing in his interoffice mail, could I come look at it? At this point it all came together and although I about died, I acted as though I had no clue why or how it came to be he was sent an interoffice envelope full of tampons. To this day, he still has no clue.