Lately I've had Dar Williams's "Are You Out There" running through my head. This is novel, since music doesn't often run through my head. So I was tuning in and out of this music, and I did a mental double-take as I realised that I was substituting lyrics from another song.
"Are You Out There" has a bit that goes:
Last night we drank in parking lots
And why do we drink? I guess we do it 'cause
but the mixing board in my head had put in:
At night I drink myself to sleep
And pretend I don't care if you're not here with me.
which is, of course, from R.E.M., "(Don't Go Back To) Rockville". I'm surprised at how well it scans in Dar's music, at a vastly faster tempo. I probably made the mental connection from the "night ... drink" phrase, but it's sort of neat, since it means my brain knows something about music.