The monitor switch
Choose two people who sit next to each other, its best if the two people sit vertically opposite each other so they can’t see each other’s screens. Swap their monitors around and you can imagine the confusion that erupts, while the rest of the office can enjoy the resulting hilarity.
The desktop screenshot
This one takes a little more time but it is so worth it. Move a person’s monitor from its usual location, taking care not to move any of the cords behind it. Try your hardest to take a photo of the area behind the screen exactly as it would look if the screen weren’t there. Put the screen back and make the photo the background and it appears like all the icons on the screen are floating, confusing the user like crazy (until they move their screen).
Play around with a colleague’s autocorrect
Go onto your victim’s Microsoft Word, go into the dictionary and edit the autocorrect for words they would use often. For example, if you’re in the furniture business change the word for “chair” to “toilet” or change lots of common nouns to be their name.
‘Make sure your colleague reads the newspaper in the morning’
This one takes quite a while so maybe save it for April fool’s but basically cover everything in your colleague’s cubicle in newspaper (or foil).
On a colleague’s computer, change all the icons on the desktop to open other programs. For example make the icon for Excel open iTunes, the icon for Outlook open Minesweeper etc. It would be a good idea to let your IT department know in advance so they can play along as your colleague will probably take your computer to them.
Mouse goes crazy
This one is simple yet effective. Most modern mouses use a laser underneath to control movement. Place a clear piece of sticky tap over the laser, then colour the tape in with a marker and their mouse will go crazy. They’ll probably bang the mouse around a bit before they think of looking underneath and it’s pretty funny.
Give a co-worker some nice greenery on their desk
This one is possibly my favourite as it’s just so unexpected. Take all the keys off a co-worker’s keyboard, and put down some cotton buds throughout the keyboard. Pour cress seeds all over the cotton buds and put all the keys back on, ensuring you can’t see anything underneath. Give it a couple weeks and there will be a nice garden growing in their keyboard.