You know when you get a tune in your head that you just can't get rid of? All day long you hum, sing or whistle it. It's usually a really annoying tune, like the theme-tune to Jim'll Fix It, or Lazy Town.

This is known as an "earworm" taken from the German - Ohrwurm Don't believe me? http://en.wikipedia.org/wiki/Earworm

I find it very amusing to infect, or plant earworms in my friends and colleagues by quietly humming or singing an annoying tune. Within 5 or 10 minutes they usually start humming along themselves. A few minutes later, they start asking why the tune is in their head. Makes me laugh every time. Give it a couple of hours and you may find that they have inadvertently affected someone else. Award yourself bonus points if you achieve this.

In the TV show Scrubs, one of the characters infects an entire hospital with "A Little Respect" by Erasure. A great earworm. If you come across any more, add them to the comments.

Finally, there are at least two things you can do to rid yourself of the dreaded earworm. But I'm not telling you what they are.