My Dad used to be in a band, he use to perform every Saturday at a club where afterwards they would have bingo. The bingo machine was controlled by someone whom they wanted to play a prank on. So the bingo machine pushed the balls up by a fan, with a spark of brilliance they came up with the idea of putting a large unfrozen fish under the air intake. The next time the guy turned the bingo machine on it let it a large whiff of rotting fish. The club was in complete confusion for a week until they removed the fish so no one would find out about the source of the smell.