Step 1: Pay Attention, This Happens Fast...
o A small "Post-It" note
o A writing implement
o A mark (actually, a mark's computer)
Write "April Fool" on the Post-It.
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.