Replying to NS: Need your help

Here is the situation.  I am moivng out of one house and into another.  Some douchebag kids are moving into our old house.  We had about 5 couches in the house, which they said they might want.  They were planning on letting us know today.

Got back today, and everything is in a pile on the street INCLUDING stuff of mine that had yet to be moved to our old house. 

I wanna get back at these guys somehow in the next day before we really need to be gone.  Any ideas?  They must not damage the house (and sadly....probably not their stuff...maybe), but need to make things as difficult as possible for these kids.  We are already going to sabotage the washer and dryer in the basement.  We were just leaving them as it is almost impossible to get a new washer and dryer up/down the stairs to the basement, so that is something, but these kids deserve more.

Come on NS.  I know you guys will come up with some good, reasonable shit.