Yes it’s probably much easier to program a software to play Tetris for you but isn’t it much cooler to watch a machine in action than just blocks randomly being dropped down?
Brianislav Kiscanin has built a Tetris playing robot using Lego Mindstorm pieces. The setup is rather difficult for me to comprehend, but a Texas Instruments DM6437 video development board watches the computer screen via a webcam and calculates the next move. It then outputs that to a grid of LEDs which the Mindstorm watches using a light sensor.
You can see a video of it in action below
The biggest disappointment is that there was no Tetris theme song and the robot didn’t run around then bang on the keys. But hey, what Brianislav has accomplished right there is already way out of my league (I can still toast that bot in any Tetris match anytime).