Does anyone else ever find random songs in their iTunes playlist that they didn't put there?

For instance, here at work I have a fairly clean playlist - it's only stuff that I happened to have at my desk, and a few CDs I've borrowed from other co-workers. However, the other day I found a Talking Heads song in my playlist. I've never owned anything from the Talking Heads, nor have I ever borrowed any of their music from someone else. So how does it show up in my 'collection'?

Same thing at home: there are quite a few songs in there that I don't recognize. I always kind of figured they were from some compilation that I got from someone else, but now I'm not so sure.

Is Apple putting stuff on my computer that I didn't ask for? I noticed that they have assigned names/albums to some things I didn't have info for, but songs I've never seen before? WTH?