The Hindu holiday Holi was celebrated Saturday March 19th (the same day the Mardi Gras Indians parade in New Orleans, see: http://bretphoto.blogspot.com/2011/03/meet-boys-on-battlefront.html) and 20th all over the world, wherever Hindus gather in large numbers.
Holi is the one where everyone throws colors onto everyone else. Colored powders, colored water, whichever. Everyone is fair game and children seem to enjoy it the most.
Once again, I recommend the always- fantastic coverage from the Boston Globe's The Big Picture.
Here are a couple to get your Holi juices flowing.