Vertical Axis Wind Turbine (Lenz)
Barely any wind yet it still turns :)

Test setup. The final version will be placed higher up

A single bolt to attach the wings makes it easy to change the degrees rotation relative to the axis (for testing purposes)

Notes/improvements
- My frame design makes removing the rotor take a long time (you have to twist each bolt off before it can be removed)
- PVC pipes (8 cm diameter) are what I used for the wings. It is cheap, but difficult to get in the right shape unless you have a way of evenly heating it (I used a 'Looftlighter')
Links
http://www.windstuffnow.com/main/vawt.htm