If this is an all out senior year nostalgia thread, I've got a good story.
So, every year they tell the senior class not to do pranks. They'll call the cops, hold our diplomas, etc. However, my senior year we had a new principle. The first day of school he asked all the seniors to come into the auditorium and said to us "you've had highschool a certain way for three years. I'm not going to ruin it for you on your senior year." aka, we got away with most anything.
Senior pranks:
1.)
Operation Floating PhallusThere were a shit load of helium filled balloons around the school. We got the idea of taking a bunch of orange peels (must have been the fruit of the day or something) and cutting them into cock shapes, tying them to balloons and whamo! Flying phallus. What we were told "oh come on, don't do that!"
2.)
Operation Close Your LegsSo, every year we do something called Snowball. It's fucking stupid and I never went to the dances and I used the activities planned to just go home and play video games. They do a frozen fish toss, however up at the field and track area. Well, my senior year it pained me to stay for the bullshit, but I did. My friends and I grabbed the frozen fish, hid it (I didn't see who stashed it), got it back in the school and threw it in a locker. A friend of mine threw a lock on it and we asked "why did you throw your lock on it?" "my lock? shit, I don't know whose that is".
It took about 1-2 weeks, but the junior hall smelled so awful. It was so hard to not laugh my fucking ass off whenever we went down the hallway. So, after the week or two went by, somehow we get called into the principal's office. There are five of us, sitting in front of the principle. He goes on to explain how the locker we had shoved the fish in was actually for a new girl who had just transferred etc. etc. etc. We kind of felt bad. The he described, in detail, what it was like when the lock got clipped (fish ooze pouring out, people's reactions) and I look over at my one friend. He was shaking so uncontrollably and was turning red. I couldn't help it, I snapped. We all broke out in laughter. Then we stopped, we realized the principal was laughing as well. He said "Just don't do that again. That was pretty funny and it's only an issue because of the new girl" And that was that.
3.)
Operation Concrete CockThis one was my idea, through and through. I had a few bags of really old quik-cement in my shed. I had an idea of making the shape of a cock on the ground in the back of the school. It was a hill, and most students/faculty went into the back. It would be gloriously exposed for them all to see (but not being in view of most children). So, we took a bunch of a rocks and cemented them together in the dead of the night in the shape of a giant cock. When we got to school the next morning, the janitors were on the phones trying to get something to break it up. Unfortunately, it was completely gone before lunch break. However, it was fucking glorious. AND, there was dead grass there for awhile