The folks over at the Milwaukee Makerspace built these fine Pot O' Gold floats to drive in a St. Patrick's Day parade. They don't seem to have build details available, however you can get a good idea of how they were build by looking through the project photos.
More:
- Cupcake and muffin electric cars at Buring Man
- Yabba Dabba DIY - Homemade Flintstones car
- The "air car"
- DeCARstruction/reCARstruction: Turning a car into a ball