Adafruit Industries takes a fascinated look at the VIDEOBLLST_R, an arm-mounted electronic buckler that projects line-art on any night-time surface you aim it at, giving you the power to produce video graffiti on demand.
If you read my fiction, you know how much I love this stuff. I've written gadgets like this into The Jammie Dodgers and the Adventure of the Leicester Square Screening, my novel Pirate Cinema, and my story Huxleyed Into the Full Orwell.
Each of 8 vector graphic pieces* is animated with Processing language and accompanied by sounds of Cwejman S1 synthetizer. Animation is triggered by pressing buttons on Nintendo Wii Nunchuk controller. The controller is connected to Arduino Uno microcontroller board, button mappings are processed with ArduinoNunchuk library and transferred via USB Serial to Raspberry Pi 2 single-board computer running Processing environment. It outputs video and audio signals via HDMI cord into Optoma PK-320 projector. Everything is powered by 5V DC 1.5A Powerbank placed in an iPhone armband. System is mounted on a rollerblade wrist guard.