Anything with peppers is funny as hell...as long as they aren't allergic to them.
1)Saran wrap over the toilet if they're a guy
2)golf ball in their shoes, that hurts like hell, trust me
3)Icee-Hot on the waistband of their underwear
4)9-volt battery wired to back of a door handle
5) seal their cell phone up in plastic bags and then freeze it in a huge bowl of water
6) shrink wrap their car, wrap "bailing" wire around there car, more shrink wrap....repeat
7) take all the buttons, knobs handles off the car
8)wrap black electrical tape around their steering wheel(sticky side out). This works better in the hot summer sun
9)if not allergic to peppers, take pepper oil and use a spray bottle to apply it to a roll of toilet paper
10) old classic, step1~ place dish of water on top of door so it soaks them when they open it.Step2~ place bowl of flower on top of bathroom door so it falls on them when they go to grab towel to dry off. 2per1 prank here
hope this helps some