sbright33:
I recommend this:
http://www.amazon.com/ThinkGeek-Annoy-a-tron-2-0/dp/B002YE3YDU
Yeah, somebody already pranked someone else in the office with one of those so I want to build my own. I figured that doing it myself will give me a lot more flexibility in what it can do. We bought a talking Leia cardboard stand-up so maybe I can make the sound motion activated so that when he walks into his office it talks to him.
I could use a relay to randomly shut off his mouse or keyboard connection, but it would have to be solid state otherwise he would notice the clicking I think.