Probably you still remember the times when TV games were popular. Now most of these games including Tetris, Snake can be found on most mobile devices. But if you want to play the magain on TV screen, then it’s time to make a simple console based on Atmega168 microcontroller.
Whole simplicity is that circuit is very easy to build it uses very few components couple resistors and push-buttons for control. Here is a video how this thing works: