Pull a Middle School Graduation Prank

You have a few days left to have one big laugh for the years of junior high. Why not do it at the very end of school?

Steps

Brainstorm. Create or borrow as many ideas as you can for your prank. Choose the most prominent public figure or icon for maximum effect. Make sure to plan out every last detail. A suggestion (Write something in the lawn in fertilizer, when it grows the school won’t be able to get it out.)
Evaluate your ideas. Eliminate any ideas that involve destruction of property, personally attack someone or can get you kicked out of school.
If you need a cover story or alibi, think of one well in advance. It should be an ordinary story, anything else will draw suspicion.
Role play the prank out in your mind. Think of how it will look from other people's (teachers, students, parents) perspectives from start to finish. Use this activity to refine your plan.
Execute your prank without drawing suspicion. If your idea involves gathering lots of materials, start early and build up slowly.

It is easy to come up with an idea that is funny to you or your friends but is ultimately a bad idea. It is much harder to come up with an idea that others will find funny and take as a good natured joke. So give yourself plenty of time to brainstorm.
If you want partners in your prank choose someone you know you can trust like a best friend of boyfriend/girlfriend
If you don't want to get caught or get into trouble your best bet is to plan and execute the prank all by yourself. Don't tell anyone. This will probably be really hard to do.

Make sure your prank is funny, not anything stupid or dangerous. Most everything you think of might be against some law, or at the very least get you in trouble with the school or your parents. If you have hurt people or property instead of making them laugh, it'll be more likely that they will pursue serious action against you.
If you think you are safe from getting in trouble because you are 'already done with school', you are wrong. You are not safe and the school board can still edit their records and discipline you. So choose your prank with this in mind.