Well you have three major cases for girls and boys
1. Your crush doesn't know you exist:
In this case, pulling a crush on him will make him think you are desperate for him. NOT a good first impression. Instead of pulling a prank on him, start up a conversation first. If you are a boy, this does not apply to you, so you still may pull a prank on the girl. Girls think this is funny, and cute.
2. You are on OK or even good terms with your crush:
Allrighty, now you can do a vast collection of things. GIRLS:Choose a hideous, ugly teacher in your school. Send your crush secret admirer letters for a week, at the end saying it was from that teacher. After a while, tell him it was actually you. This will also be a great conversation starter.
BOYS: Do something like fake towing her car, or anything which you see on punk'd.
WHATEVER YOU DO DON"T DAMAGE THEIR PROPERTY OR EMBARRASS THEM IN FRONT OF THEIR FRIENDS, as this leads to resentment
do something funny
=== ===
pull a prank on him
When they are sleeping put a table over there head and make a loud noise which wakes them up causing them to smash there head on the table :)
You can view videos of the skirt pull prank and learn how to perform it from the videos at the YouTube website. Once on the website, type "Skirt pull prank" into the search field at the top of the page and press enter to bring up the information.
they drew on his face
Peter put a dead mouse on Mr. Dussel's bed as a prank.
Put gum in his hair
A fart machine in there desk
Give someone a swirly or wedgie
wghehgdbhrs
you can put jello in his shoes