In my school, one day the boys got together to shout "bhago bhago" just when the class was about to get over. It became a very serious matter involving the principal too. He threatened the entire class with punishment unless the guilty persons owned up. One of our classmates admitted that he only said "bha", he did not say "go" as the teacher had turned around by then. This amused everyone and we were let of with a small punishment. :)
Well something similar happened when i was in class X. The library was lit up with lights which were distributed across two phases. Once one of the phases went kaput, and we the perennial back-benchers found ourselves in the darker part of the library. I initiated a 'Andhera Kayam Rahe', inspired from the crook in the Shaktiman series, which soon spread like woildfire. Things took an ugly turn, and I was taken to the principal on admitting that I had done it. Luckily the punishment turned out to be much lesser than was promised initially.
Cheers, Debarshi