Riddle: While sitting in his living room one evening, Jim thought he heard some voices outside. At that same moment, he observed a dark blur quickly pass by his window, just as daylight was fading. He saw it return to pass by his window a second, a third, and a fourth time. Thinking it must be a bird or a bat, Jim thought little of it, until about 20 minutes later when he saw the same blur pass by his window --- but this time it was a dull greenish color! He immediately jumped to his feet and ran to the window, just in time to see a glowing disk-shaped object hover, and then land on top of his neighbor's roof where it remained motionless. Jim watched for a long time, as it slowly began to lose its glow. He considered calling the police to report a possible U.F.O. sighting, but he didn't want to risk becoming a "community crackpot", so he decided instead to wait until morning to see if the strange, glowing craft remained on the roof where it had landed. What do you suppose Jim saw on his neighbor’s roof the next morning?
Answer: The "U.F.O." Jim had seen was a black frisbee two kids had been throwing in his back yard. As it began to get dark, they switched to a glow-in-the-dark frisbee to see it better. Unfortunately, the first time they threw it, they quickly ran off, as they saw they had thrown it onto the neighbor's roof, and they didn't want to get into trouble.