Called Beer Can Keyboard, this awesome piece of work uses Ardruino to send signals from the beer cans to any computer. It does not use any buttons, instead it uses the capacitive technology, much like the the touchscreens from the smartphones. It was created by Robofun. Details here.
You do not need to press it, you only need to touch it. It was showcased on 29th September 2012, at Webstock 2012 Social Media Conference in Bucharest (Romania), where I was invited as blogger. In the video you can see how people insert their emails to be subscribed in a contest. I used my email too and hope to win a trip outside Romania, to Prague.