April Fool: the World's Simplest Stupid Office Trick

This instructable details a simple stupid trick that takes 30 seconds to set up, yet still gets a laugh.

Step 1: Pay Attention, This Happens Fast...

You will need:
o A small "Post-It" note
o A writing implement
o A mark (actually, a mark's computer)

Step One:
Write "April Fool" on the Post-It.

Step Two:
Put the Post-It on the bottom of the mark's mouse, covering the sensor.

Yes, it's stupid. It still catches people all the time. We just don't expect things that simple not to work.
Yes, I know the pictures are lousy. So is my cell phone's camera.