You will need
- tape, scissors, access to computer colleagues, screwdriver, paint, a few stickers
Stay in office a little longer than usual. Seal with tape all the computer mouse so that the optical control was blocked. Joke will be when all of the computers in the office suddenly lost control. Employees, probably, will start to get nervous, to call the administrators. Importantly, at this point not to confess and also to portray a distressed employee, who does not work a mouse. Similarly, you can seal the inputs of the keyboard and mouse to the computer.
Change all the buttons on the keyboard sometimes. This is easily done with a screwdriver. Those who frequently works at a computer will not be in awe of the fact that now have a long time to restore the layout on the keyboard.
Stickers cover the entire monitor. The more stickers will be glued, the more time a colleague will spend on the cleaning paper.
Glue the workplace colleagues paper or adhesive tape. Under the workplace refers to a table, a chair, a computer and other office equipment.
Replace all writing pens in the office on "marriage" or dip the pasta in the varnish. Will be very funny when your colleagues all at once will not be able to use when writingonthe equipment.
Change glasses. If you know what glasses diopters uses your colleague, change his glasses with the opposite effect. This "trick" will only work if the employee is overevat glasses only for work with documents or computer. If the person wearing them, not removing, is unlikely to play a trick on him.
Seal from the handset microphone tape. Any attempt to call will be for your colleagues "test of strength", because to repeat several times the same is a very difficult and unpleasant.
Any joke should be harmless joke. Otherwise, a mockery of human rights can admit a criminal offence.