What's a song you memorized against your will?

So the title feels kind of aggressive, but let me explain. Back in grade school we used to do a lot of school plays/performances (at least two per year), and so I have a bunch of songs rattling around in my head that I never wanted to learn. The only one I really enjoy to this day is Happy Together by The Turtles. I'm 33 now, and that was back in 6th Grade.

So what songs are like that for you?