When I was a little kid my mom would always play the same joke on my siblings and I. She would look out the front window and say, "Look, it's Big Bird!" And, of course, we would go running for the window and she would say, "April Fools!" Why did this work several years in a row? Cruel mom!
So anyway, in the spirit of April 1st, here are some sites you can go to for inspiration for your own pranks!
One time my friend and I went around to friends and put post it notes all over one brother's car at work and then wrapped the other's in cellophane. Good times!
Have fun, and be nice!