The fantastic brightness of LED screens makes them one of the pinnacles of display technology for large events and installations. However their relative expense and size makes them inaccessible for smaller venues or budgets.
Enter Evil Mad Scientist’s Peggy LED board. The Peggy 2.0 board allows the 25×25 LED to be addressed individually, and Jay Clegg’s Peggy Video project takes advantage of this, mixing in some Arduino (on CDM)and Processing (on CDM) to create a 625 pixel screen capable of 30FPS, monochrome video.
This isn’t a simple, off-the-shelf solution, and it’s still reasonably expensive: The Peggy boards cost US$95 without LEDs ($190-265 with), but if you want to add LED video to a project, this is probably the best combination of cheap + accessible you’ll find.