Small Whirly copter with a spiral spinner stick
The STL's are scaled to a height of 150mm as that is the max for our printer. The copter is ~80mm diameter. It's small but we were making small toys to give away at a fund raiser carnival. Two sets with supports under the blades requires ~7m of 1.75mm filament.
Also attached is OpenScad file adapted from seedwire's 'The Whirly One' http://www.thingiverse.com/thing:36217. It should be possible to change the turns per cm of the spin stick and the blade pitch/thickness/width. You can generate STL's from the scad file for many configurations.
You can see a quick demo of it here: https://www.youtube.com/watch?v=lJM2tqc2pL4