Around me there is something called the Cardboard Classic. Every year one of the radio stations hosts this up in the mountains. The goal is to build the craziest thing you can think of and then race it down the mountain. Most of them fall apart before making it far but you see some really crazy stuff. A couple of my friends one year built a full stage and bar out of cardboard and had a band playing on the stage and serving drinks as the thing went down the mountain. It was pretty insane lol.
Here’s some other pictures from cardboard classic.