I'm trying to figure out what to do for April Fools Day. Any ideas?

Please:
Nothing crude, messy, or that takes a ton of work. I want it to be funny, but not embarrassing to either myself or the person being pranked.

I have a little sister (9), my dad and my mom living with me. Just to give you an idea of what I could do, here’s what I did last year.
I unrolled the toilet paper in the bathroom, and before rolling it back up I stuck a dollar bill in it so that it would get rolled into the toilet paper. My sister found it. It was really hard to keep a straight face when she found it, so they knew it was me. Another thing: I would love it if I could put a camera somewhere near and record their reactions.