Practical Joke

Here is a joke a friend of mine played on someone. It actually made the Dibert newsletter:

A co-worker of mine has SETI@home running on his computer. This is software, distributed by SETI (Search for Extra-Terrestrial Intelligence), that will run on PCs as a screen saver and analyze chunks of data from a radio telescope looking for non-naturally occurring signals from outer space. The other day I copied the SETI analysis screen to Microsoft Paint and then edited it to contain a large alert message stating that ET signals had been discovered. I also drew in a button that he could use to "Notify SETI Immediately." I left this image on his screen with a "red alert" sound running in the background.

When he returned to his desk he was ecstatic to see that he had found ET life. He called another co-worker over to witness the historic moment. Then he clicked the button and discovered what I'd done.