So far harmless, more or less, pranks. I did worse in college.

My best friend and I rigged her house while her parents and brother
were out. We actually set up a Super Soaker to spray them in the face
when they opened the front door. We put duct tape over the light
switches so they had to go in in the dark, and then we'd hung stuff on
ropes from the ceiling for them to bump into (soft stuff, like stuffed
animals and clothes). Finally, we put a scarecrow with a frying pan
in its upraised hand int he corner. Her mom screamed thinking it was
a burglar.

Good times.

--Fil