"Buzzing" is a fun way to get a friend's attention. If you have an instant message window open and you click the "!" in the starburst just above the field where you type your message (or press Ctrl+G on your keyboard), the instant message window will "wiggle" and both you and your friend will hear a funky buzzing sound. (Keep in mind, you can only buzz ‘em once. Don't want to overdo it!)