Convinced that the neighbors are up to no good, but reluctant to call in the fuzz without some evidence? Buy a Spy Kite for the little ones, and let them gather the dirt for you! The Spy Kite couples a light-weight fiberglass frame with a digital camera that can snap blackmail material from a height of 80 feet.
H&R readers: Creepy violation of neighborhood camaraderie, or just plain ole' fun? (Alternative question: Would something a little more obvious be any less offensive?)