I bought a Peggy2 Light Emitting Pegboard Kit from Evil Mad Science.
The Peggy2 is a 25 by 25 array of 10mm LEDs controlled by an Arduino. You can write interactive programs to display anything on it. I actually found it by searching online for a circuit that does just that. I am very excited to play with it. While I am waiting for it to arrive, I am writing a program that will convert a bitmap image into the Arduino code needed to display the image on the Peggy2.