Office Poltergeist

Office Poltergeist is a program that allows you to take limited control of another's computer and prank them.
It allows you to:

1. Play spooky sounds
2. Open or close CD drives
3. Transmit text through your victim's keyboard
4. Make windows shake
5. Turn monitors on and off
6. Move windows slightly left and right
7. Send popup alert messages

All you have to do is set up the client on their computer and it will give you their ip address.
Office Poltergeist is open-source and released under the GPL.

There is also a Firefox extension which is even easier to install and adds the option to replace text and open webpages.