For a long time, humanity was wondering how could a computer make coffee... People need coffee wake up and stay awake in front of the computer for a long time. Everyone knows that coding is better at night...
The main problem is how to manage the coffee machine with the computer, so that it will be controlled by software. This generally means an ON/OFF switch implemented as a circuit which controls the coffee-machine's power supply.
This HOWTO has turned out in a public project, look at http://coffee.sourceforge.net/,