Saturday, April 4, is International Pillow Fight Day, with combatants in more than 75 cities worldwide participating. (The photo shows Vancouver's 2006 pillow fight). The official Pillowfightday.com Web site isn’t clear on the origins of this global pillow-pugilism party except to say that “organizing a massive pillow fight is perhaps the simplest of free events or interventions, but also one of the most rewarding.”

The site also includes information on how to organize a mass pillow fight. Early afternoon is preferable, although the event founders note that this “will necessarily lose those hungover souls whose Friday nights ran quite late.” A large public square is the ideal location, and social-media sites like Facebook and Twitter are best for spreading the word.

As for which “weapon” to use, Consumer Reports hasn’t recently tested pillows, but in general, soft ones are ideal for stomach sleepers and pillow fighters. Anything firmer could result in bloody noses or other injuries, which are as bad for pillow fights as stiff necks are for a good night’s sleep.—Daniel DiClerico | e-mail | Twitter

Essential information: Read "How Did You Sleep Last Night?"  for advice on choosing sound machines and separating sleep myths from realities.