This project is a great little LED portable game system based on PIC16F628A. It is equipped with a 4×4 LED matrix, a PIC microcontroller, 9 bipolar transistors, 4 buttons for control and one switch to power on. It is also has a small speaker to generate game sound. It is powered from 4 Ni-MH batteries. Check this instructable on the link below. So far it has only three games programed.
Portable Led Game System – [Link]