Pie in the Face

For those of you who watched the comedy clips, most liked the 3 Stooges Pie Fight. The 3 Stooges are famous for being dumb, but obviously their humor still makes modern audiences laugh.
The "Pie-in-the-face" gag was featured in film as early as 1914. The Keystone Cops (who were clumsy policemen chasing a burglar) featured it regularly. The comedy duo Laurel and Hardy had a giant pie fight in their movie "The Battle of the Century." It is rumored that over 4000 pies were used.
Other comedians, like Charlie Chaplin, have used the pie fight, and even cartoon characters like Bugs Bunny use the gag. But "pieing" hasn't been used just for laughs. Pieing has also been used to make political statements, and if it is done to someone who doesn't like it, it can be considered assault! So remember, if you are going to throw a pie at someone, make sure they have a good sense of humor, or you could get in trouble.
J told us that sometimes people are hit with a pie in the face on their birthday. I was wondering, though, what other pranks (funny tricks you do to people) are popular with you and your friends? Have you ever done the pie-in-the-face to trick someone? What do you do to have a laugh or make other people laugh?