http://www.thinkgeek.com/gadgets/electronic/b278/
Edit, also fun, assuming it wouldn't get you fired:
http://www.thinkgeek.com/gadgets/electronic/ae83/
I love how most suggestions are for messing with his PC when teh OP stated no one has access to his account.
http://www.techbuzz.in/shortcut-key-to-flip-the-screen-in-the-windows-to-180-degree.php
But also turn his monitor upside down, so it's displaying correctly. You may have to enable this rotation.
Just be sure that whatever you do, it's epic enough to justify getting fired.
Horseplay and pranks have no place in the workplace.
[/ adult mode]
When you're operators of heavy equipment, I can see that.
When you're a keyboard jockey, not so much. Have to do shit from time to time to break the monotony.
