Secret Satan

Less an invention, more of a fun office game. For a month every year (likely summer, weather is nice, people are often more cheery) offices in question would assign each employee the name of another employee, and give them the month to pull some variety of prank on that person.

Aside from health and safety guidelines, there would be no rules as to the nature of the prank to be pulled. It could be anything from jumping out and yelling 'boo', to a devilishly intricate plot involving pulleys, levers and a series of well bred llamas.

There would be no ranking or scoring system. The best are determined only through the age-old system of office politics. Anything that will humiliate or anger the prankee is to be heavily frowned upon. The aim is to create an air of joviality, not a climate of fear. Nor should these jokes be allowed to interfere with general work. Of course, there is no requirement to actually perform the practical joke, but that person would run the risk of being seen as miserly by his or her colleagues.