A cardboard regatta, is race on a calm body of water between contestants that build their own cardboard vessels. This is a particularly good event for groups that have a technical or engineering focus. Each team is given a pile of cardboard, several roles of packing tape, and a paddle with which to build their boat from. These are the only supplies allowed in the boat’s construction. Knives or scissors may optionally be given as tools to aid building. In most cases there should be a time limit. Prizes should be given for the winners of several contests, such as most creative design, race winner, and longest floating vessel. You can charge an entry fee for each team participating. You can have a concession stand to sell refreshments to contestants and bystanders. If your local laws permit it, you could have gambling booth to take bets on winners, with a cut for the house. Don’t forget safety, have a rescue boat and life jackets ready!