Farblog

Send them random emails throughout the day that make no sense.

When they start to get confused ask them what they are talking about and make a “You’re Freaking Crazy” look with your eyes.

When they start getting mad at you, swivle the chair around, get up, walk over to their desk and press the power button on their computer.

No doubt they will get upset.  In retaliation just say, “You should have saved your work”