While browsing around I found a site dedicated to annoying people with Bluetooth enabled cellphones and Pocket PCs.
BlueJackQ has coined the term BlueJacking which is basically taking your Bluetooth enabled device and creating a new contact, but instead of giving it a name, write a message instead. Suggestion: 'Hello, you've been bluejacked', in the 'Name' field. Then you can search for other phones with Bluetooth and send that phonebook contact to them. On their phone, a message will popup saying "'Hello, you've been bluejacked' has just been received by Bluetooth" or whatever your message says.
Read their guestbook to find out how others have succeeded in annoying drunks, finding dates and other Bluejacking antics.
Have you ever been bluejacked? If so, tell us about it.