The little DIY phone isn’t cheap by any means, but it’s still a phone you can build entirely yourself. The system uses an Arduino, a touch shield, a GPRS shield and a few other components. Then, it’s as easy as clicking everything together, loading up the code into the Arduino, and making your first call. It’s actually not too complicated, and you’ll certainly be the only person at the party with a phone you built with your own hands. Head over to Instructables for the full guide.