Here's a cute way to gimmick a keyboard out of a grid of beercans, using Raspberry Pis and Arduinos:
We did this at Webstock, event which took place in Bucharest in September. Staropramen, one of the sponsors of the event asked us for an innovative way to offer a trip to Prague to one of the event's guests.
So, we came up with a keyboard made out of 44 Staropramen beer cans. Each beer can was a key, and whenever someone touched it, the corresponding letter appeared on a large plasma screen (just like any regular computer keyboard).
And the surprise was fantastic! The user experience and engagement overcame any expectation. Every single person who attended Webstock tried the keyboard and participated to the contest.
Behind the scene, the system is built around an Arduino board and a few capacitive controllers (just like the ones which are inside smartphones' touch screens), connected to a Raspberry PI board which controls the plasma screen display.