"accidental" voyeurism?

The question about the "most trope-like situations" gave me the idea. We all know (and love?) those moments in anime and manga, were some form of accidental or "accidental" voyeurism takes place. But have you ever encountered something like that in rL? Either as the "looking party" or as the one looking one? Lets hear it!

Can be funny, can be hot, can be whatever you like. As you may tell, I'm too bored to make exceptions :D