We always play jokes on Mom. I remember the time when we put cigarette poppers in her smokes and then TRIED to wait patiently (without giggling) for her to light a cigarette.
The worst joke we played on her involved Freddie Kruger. We have a life sized standing cardboard cut out of him. Well, we decided to put it in her bedroom before she came home from work (she lived with us for about 2 years). It was dark and when she turned on the light HE was standing there. Scared the shit out of her......I felt really bad at the time, but we still laugh about it now.
We don't do anything cruel like that anymore.....she is getting too old to scare the shit out of her now! :-) Poor Mom!! She is really a good sport though! One day she will get me back.