Bonfire is an agreement between users to burn ETH with the intention of making ETH more rare and more valuable. Each pledge to the contract also gives the user an opportunity to be randomly selected for an award in ETH. Pledges are around 1 to 5 GBP depending on which bonfire a user pledges to. 55% of the ETH pledged to the contract is eliminated in a coin burn. Try it out free on the Rinkeby network.