What would your senior prank be?

I don't know if I would be able to be part of a senior prank considering how much trouble you could get into especially if you are 18 or over. I know that if I would it be like tp'in the school yard and spray painting the grass saying class of 2012 and then just going to my last day of school and wearing what I want and doing what I want. I wouldn't be apart of anything that could seriously get me in trouble.