Here it is, the first Ethereum coffee machine. I hooked up a classic 'Technivorm' coffee machine with a full ethereum ropsten (testnet) node running on a raspberry pi. I check for incoming transactions every 30 seconds. If the right amount (0.02 ether) has arrived in my wallet the raspberry switches on the coffee machine for a minute or two and the smell of fresh coffee fills the air.
We will do a 'blockchain in practice' series of workshops at our campus. This is an example and an effort to make blockchain software more 'visible' and fun.