CarTalk recently asked for listeners' best practical jokes. I especially liked this one:

Back in college, we used to live in these "suites," which were basically four corners of a building with rooms on the outer edge and a living area in the central part. The person who lived in the corner room was going away for the weekend, and the rest of us decided to play a joke on him. We went to the hardware store and bought some drywall, paint, electrical wire, etc. We then proceeded to plaster over the door to his room. We even went so far as to move the lighting fixture near his door to right on top of it. When all was said and done, his room had disappeared.

When he arrived back on Sunday night, we all pretended he didn't live there (to the best of our ability) and despite his confusion we kept up our end of the farce. We made him sleep on the couch in the living area that evening, then the next morning we broke through the wall and let him back into his room.