Lol i love pranks.

My mate was at his cousins and his house has like no security. so we booby traped his house buy making doors open when he opened somthing else. he opened his door and bucket of feather fell on him. he also has a massive kermit doll so we hung kermit up in the front lounge with a knife in his hand. When he came home he was like WTF? and was trying to figure out what the hell it was. (bearing in mind he was paro)

OR what you can do is when they enter the house kill them all bet they won't see that coming.

OR kidnap them. jump them, from behind and lock thier asses in a trunk for a hour or so.