Lately I've had great fun with the miniature quadcopter Hubsan X4 H107C. I've already lost the first I got, and the second was this one from Deal Extreme. Right now, they all seems to be sold out, but there are hundreds of other brands to choose from in all price ranges. Starting with this single axis "flying saucer" at only $15. The first quadcopters start at about $30, and most of them seem to be copies of the Hubsan. They have a Walkera with GPS hold starting at $333, all the way up to the 6 channel version which supports First Person View (FPV) glasses.
For the Hubsan X4, there are a few extras to get. First of all, the propellers will break, so make sure to get plenty of replacements. Also be aware that they are directional, so there are two of each kind in a bag. A few extra batteries are nice, since a single one will only give about 8 minutes of light time with almost an hour charge time. So to avoid spending hours charging them, some extra chargers also come in handy. Finally, a micro SD card is required for the camera; 2 GB, or even only 1 GB is plenty.
And up and up it goes! Until the wind takes it away, it lands on an inaccessible rooftop and you'll have to get another one. :-)