Since April Fool's Day is on a Sunday this year, there are not as many opportunities to prank your co-workers but here are a few fun ones to try anyway. You need access to their PC for these.
Go into Word and set up the AutoReplace with something funny and irritating. You can be obvious and have the system replace a common word like "the" with an insult. Or delay the agony by making more discrete changes such as a misspelling of your company name.
Everyone has access to a wireless USB remote control for PowerPoint presentations, right? Sneak the wireless receiver into the victim's USB port and then when you are ready, and in range, start messing with his mouse movements and clicks.
See more geeky pranks for April Fool's Day