April Fool’s Day (aka All Fools’ Day) goes back at least to the 17^th century in England. In 1698, someone invited lots of people to go see a fictitious “washing of the white lions” at the Tower of London (where they used to keep the menagerie). It worked so well that some bright fellow in 1860 decided that the prank deserved a repeat and actually sent out invitations to the “washing of the white lions.” Several people showed up, only to find that there were no longer any lions at the Tower, much less any that needed washing.