Solar Powered Cat Tantalizer
Unlike fireworks, entertainment by way of watching cats have a conniption represents easy, inexpensive, and safe* entertainment 365 days a year. Now we all know how I feel about cats, i.e., Satan and Joan Rivers' love children, but in setting aside my animosity for a moment I can see that this Solar Powered Cat Tantalizer is truly a gift to those of the feline persuasion and, more importantly, their owners' overnight guests, who would really appreciate it if they went and played by themselves over by the window instead of sitting on his face in the morning.
When suction-cupped to glass, the Cat Tantalizer's attached plastic ball and feathers do a come-and-get-me dance every time its solar panels feel the sun's driving rays. This entices cats to hunt and pounce and make eejits of themselves. The contraption requires no batteries or maintenance--unless it de-suctions and falls off the window, which will inevitably happen on a semi-regular basis, and usually during moments of complete silence when the crashing tumble can best scare the bejuniormints out of you--but uses its solar cell to activate a motor that churns the attached rod and toys back and forth. The rod also detaches should a human want to take on the responsibility of playing with the cat him or herself.
*Note: I truly believe that cats are crazier than women, so I wouldn't take the "safety" of passively watching them grow increasingly agitated trying to catch and kill a toy for granted. Be prepared for them to tire of the Tantalizer at any moment, and opt to turn their claws and teeth and deadly piss shooters on you.