Midomi is a really cool site that lets you hum or whistle the melodies of songs you’ve forgotten and it will try to provide a match.
I was able to get it to recognize a Beatles song and “Row, Row, Row Your Boat” but had less success with a couple other (slightly) lesser-known songs. But still, pretty amazing technology and who knows, maybe my humming just isn’t up to snuff?
Oh, and May the Fourth be with you!