Make black and white mural art from photos
This project is the only closed source one we're featuring, but it's too cool not to mention. The Blackstripes team has created a Raspberry Pi-powered spin off of a "V-Plotter" style artbot. The Raspberry Pi turns a photo's bitmap data into vectors that is drawn with a robotically controlled marker, resulting in beautiful black-and-white murals that look like works of art. While the team isn't letting others in on their source code, you can commission a print of one of your photos for about $200.