The best April fools jokes

Write a message on an upside-down paper cup that alludes to something horrible being trapped under it. Leave it on a coworker's desk or in a conference room.
Vote: has 62.22 % from 20 votes. Send joke:
More jokes about: April fools, office
Change the coffee in the office coffee maker to decaf.
Vote: has 60.56 % from 19 votes. Send joke:
More jokes about: April fools, office
Hide an alarm clock in someone's bedroom and set it for 3:00 a.m.
Vote: has 59.93 % from 25 votes. Send joke:
More jokes about: April fools, time
April doesn't fool Chuck Norris, Chuck Norris fools April.
Vote: has 53.58 % from 21 votes. Send joke:
More jokes about: April fools, Chuck Norris
Pull on a coworker is to press ctrl+print screen on their workstation, then paste it into Paint, save the pic, and set it as the desktop background. Move all of their icons to the trash. When they get back to their desk, clicking won't accomplish anything!
Vote: has 47.37 % from 18 votes. Send joke:
More jokes about: April fools, computer, office
I just recently discovered that there is a national holiday named after Atheism. April FOOLS day. Like this story in the name of Jesus.
Vote: has 34.25 % from 36 votes. Send joke:
More jokes about: April fools, christian