I haven't played any jokes yet, but this is what my boss did. She always gets into work way earlier than the rest of us~she cut out little squares of white card-stock, wrote April's Fool on them, and placed them over the roller on the bottom of the mouse. You should have seen everyone trying to figure out why their mouse wouldn't work. Not the funniest I've ever seen, but it was a good laugh in the early morning.
