San Francisco is making me believe it might be the coolest place on earth. These amazing and creative fighters reuse cardboard and cardboard tubes to create elaborate armor and weapons and then go into battle! They are called The Cardboard Tube Fighting League and they remind of the Pillow Fight League here in Toronto except maybe a bit more on the reuse side of things.
The granny is my fave. See her below the fold.

This is serious creative and amazing stuff. The rules will show you why:
1) First Rule of CTFL: Don’t break your tube. In a duel, the last person with an unbroken tube is declared the winner. In the event that both participants break their tubes at the same time, the game is a draw, and both duelists are considered losers.
6) To participate you must be using an official CTFL tube, which will be provided at the event, and have signed a release waiver.
9) Shields are officially banned in tournaments.
There doesn’t seem to be any rules about armor (except no shields) or any point given for creativity but that doesn’t seem to hold people back from going buck-nutty.