I’ve just ordered this book about April Fool’s Day by Martin Wainwright. It covers both the history of the day itself, as well as some of the most well-known April Fool’s jokes, such as the island of San Seriffe and the Spaghetti Harvest. With a bit of luck, it’ll be here in time for this weekend as I imagine I may be spending at least part of Saturday sat around waiting for people.
In a similar vein, Wikipedia is bracing itself for April 1st. It’s apparently one of the worst days for wiki vandalism.