No big problem, right?
Well the next morning, I could not figure out why on earth I had a pocket full of sunshine. It's the only thing that was going over and over in my head. "I've got a pocket full of, pocket full of sunshine..."
The other guys show up at the rental van and I ask them if they've got any idea why I've got a pocket full of sunshine and they've got no clue. It doesn't keep them from razzing me about it, but they've got no idea where it came from until we hear it later on the radio and it all becomes clear. I remembered having fallen asleep to VH1 and must have heard the song during a cycle of sleep and got it stuck in my head.
I don't think anyone really knows why certain songs get stuck and others don't. If you're lucky, it's a goodie. For those who only have the tune and not the lyrics... there's hope for you yet.
I've got an internet buddy who homeschools his kids in HI and tours the world playing piano. We've chatted each other up from time to time. I listen to his music quite a bit (Dan88 I recommend Chopsticks, and Michelle) and he's tuned me into a couple of sites like Free Range Kids
This one, I found on his site today (probably seen it there before, but didn't click through.)
Simply hum a bar or two into your microphone, and they find the song.
Give it a try and see either how good/shoddy of a match they make, or how good/shoddy of a hummer you are.