by Mike Krumboltz April 1 is the only day of the year when deceit and pranks are not just tolerated, but encouraged. Interest in the "holiday" is palpable in the Yahoo! Search box. Web lookups for " best april fools day pranks ," " how to trick a friend ," and " funny april fools day tricks " are all making more noise than an overinflated whoopee cushion. But if you ask us, the most interesting prank-related query is this: April Fools' Day history .