idea 1 - just walk around where you live with some friends, yell the most obscene words you can think of at the oldest people you see. then run like its going out of style, if they chase you dont worry, their old and slow, and probably dont know the words your using, its still funny. bonus points if their deaf and you follow em around for miles.
idea 2 - dye your hair blue, go to school looking really depressed and tell everybody its some weird disease, then get your close friends to do it too, this is really funny because even your teachers might believe you, make sure to say its contagous. extra points if they call home to "ask the rents"
idea 3 - go to the mall and just run around screaming, really good after an exam or test. i like this one because it really freaks out the eagles and they will probably make fun of you, if they happen to be from another school you probably wont see em again so its cool. when they talk shit walk up to them and even plow through em all screaming, tell em their all fruity and ask where you can get some hot new american eagle clothes.
idea 4 - go into american eagle and ask the dumbest looking clerk (often a tough choice) about every piece of clothing. ask for tickets to the annual barn dance or ask what size their custom surfboards are. this is my personal favorite because they will always tell you "theres no such thing", then i want you to scream "then WHY THE FUCK IS IT ON A SHIRT!!!!". they will be really embarassed and might actually wet themselves. extra points if they do.
idea 5 - find some random on icq and ask them personal questions about their pets, i dunno why i just bet youd get some funny answers. bonus points if you put exerpts in my guest book.