I like to change my email signature daily to include one-liners from songs that people get stuck in their heads. Nothing pleases me more than to get an email or phone call later that day from someone who's complaining about having one of my songs stuck in their head.
"Here's a little song I wrote, I learned to sing it note for note,..."
"You can check out any time you like, but you can never leave..."
I can usually get a couple people. Commercial jingles also work, depending upon the audience.