Click the button. Sing or hum a part of a song. See if their database search can recognize it.
Strangely, the only songs I could manage to think of to sing were by ABBA. That’s just weird. But the search correctly identified “Take a Chance on Me,” “Mamma Mia,” and “Dancing Queen,” all sung with “da da da” instead of words.
Firefox with flashblock wouldn’t play it, though. I had to switch to IE. Bummer.