The seniors before us let out an entire box-full of the dissection frogs into the hallway (our school was really tiny, just one floor) and watched as people either freaked out, laughed, or wandered around very confused at all the frogs running around.

Our class let loose two chickens (one rooster, one hen) in the yard of the school--they've taken up residency because no one can catch them. We named them One and Three and the students still get asked what happened to Two? This is in the city by the way, but they were surprisingly lenient on us.