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.
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has 58.52 % from 27 votes. More jokes about: April fools, office
Hide an alarm clock in someone's bedroom and set it for 3:00 a.m.
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has 57.35 % from 29 votes. More jokes about: April fools, time
Change the coffee in the office coffee maker to decaf.
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has 56.98 % from 23 votes. More jokes about: April fools, office
April doesn't fool Chuck Norris, Chuck Norris fools April.
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has 54.15 % from 24 votes. 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!
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has 53.62 % from 34 votes. 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.
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has 30.73 % from 79 votes. More jokes about: April fools, christian