Some general guidelines.
1. A good prank does not cause physical injury to anyone.
So, no pushing people down stairs or doing Jackass stunts. Medical care can be expensive. Seeing someone bleeding, with a broken bone, or missing teeth is not funny.
2. A good prank does not cause property damage.
Damaging property is malicious, can get you in serious trouble, and also is not funny. This applies to personal property (clothing, computers, cars) and also for college property - buildings, sports fields, trees, etc. If Physical Plant has to come clean up, it is NOT a good prank.
3. A good prank does not make people feel negative.
If your prank makes someone feel humiliated, ashamed, or embarrassed, you fail. That is bullying. If your prank enrages someone, you fail. A prank should be a mild but funny inconvenience for your target. If someone feels ashamed or angry, this means you have misjudged things and taken your prank too far. Apologize and try to make amends.
Also, some people can be very sensitive about being on the receiving end of pranks or friendly ribbing. Please keep this in mind when choosing your target(s) and planning your prank. Really try to think of how your target will respond and feel.
4. A good prank only affects the targeted person (or group of people).
The first two 'rules' show that when someone else needs to come in and clean up the mess (whether doctors, Physical Plant, or campus police), you've messed up. This rule is essentially the same. If you want to prank Susie Q, don't disturb her roommate at 3am, and don't disrupt her biology class. Very simple.
5. Don't prank the campus tours.
Your college is trying to woo future students in an attempt to get money (tuition, fees, room & board, the ridiculously priced textbooks). Messing with tour groups will not win you any points with Admissions or any other college administrators. You can be punished. I know of one person who was actually suspended for streaking a tour group. Keep that in mind.
6. Don't prank professors.
This should be obvious ... but I will put it out there anyway. Professors are not your friends and are strictly off-limits.