I had to share this. This is an excerpt from Michael Moore's TV Nation, which aired in the mid 90s (those were the days).
Without giving too much away, this documentary crew hires an actor to pretend to be a serial killer. They rent out a house for him on long island, and see just what it takes for his neighbors to realize foul play is afoot.
For those of you who wanted to try planting mikes and spying on people last night, get ready to be happy. The residents of this sleepy burg have no idea they are being watched.
This whole series is great, so if you like this, check out the rest: