Nick Hall builds a LED Pong clock, project files and source code is included. [via]
This project uses the classic video game Pong to tell the time. The 2 players automatically win and lose so their scores reflect the hours and minutes. The clock can also show the time written in words, or with large or small digits. Two buttons allow you to set the time and change the clock mode via a menu screen. The project uses 2 LED matrix panels from Sure Electronics, an Arduino, and a DS1307 clock chip.
LED Pong Clock – [Link]