Everyone likes GBC's (Great Ball Contraptions). Know you can build your own out of one NXT1.0 kit plus an extra 40 tooth gear! Here is a link to the building instructions: http://www.nxtgeek.blogspot.com/2012/04/building-instructions.html You can read more about the original project here: http://nxtgeek.blogspot.com/2012/03/circulator.html
Enjoy!