I've had this happen to me once with my Glide.
Even one or twice with my old x10.
Sometimes I just think it's a runaway process gone crazy.
But for my glide, I know I downloaded and was trying ADW launcher and it happened the next day. I uninstalled it. and haven't had any issues since.
If I see the problem again, maybe I'll connect it to Eclipse and see if anything shows in the track stace.