ETH93 is a smart contract on Ethereum that automatically runs a lottery each day and gives a cut of ticket sale revenue (5%) to an established charity, with 93% of ticket sales going to the days winner. All smart contract code has been verified and published on Etherscan here:

https://etherscan.io/address/0xdd2ee38f9993c0bc1c1b5b9798bc4deff66cac4a#code

You can also read more at the website - https://www.eth93.com

How does the lottery work? The Oraclize smart contract is used to query the random.org API, which generates an entirely random number that will be used to pick a winner. As an example, if 500 tickets were sold, a random number between 0 and 499 would be generated. If the random number generated was 233, the owner of the 234th ticket purchased would be the winner. At a ticket cost of 0.01 Ether, the winner of this lottery would receive (0.01 * 500 * 0.93) = 4.65 Ether and the charity we donate to (Heifer International) would receive (0.01 * 500 * 0.05) = 0.25 Ether.

To our knowledge this is the only decentralized app that gives a cut of revenue to an established charity. We also see transparency as a massive advantage, and an essential part of this service to ensure that users know the ETH93 smart contract is doing what we say it does and nothing else. We strongly welcome any criticism of our smart contract code, and invite anyone with Solidity knowledge to pick apart our contract.

We may run an ICO in future, and in fact 1% of ticket sales go to a contract that can be withdrawn from by future token holders, though for now we are just focused on getting the word out and providing a great service.

To participate in any days ETH93 lottery Ether can simply send to the smart contract address: 0xdd2ee38f9993c0bc1c1b5b9798bc4deff66cac4a. Every 0.01 Ether you send will get you 1 ticket. There is no limit to the number of tickets you can purchase. The more people participate in any days lottery, the lower your chance of winning would be but the higher the jackpot.