I wrote a small proof of concept for a game I came up with called Rotris.
The object of the game is to clear the game field and make as many matches as possible.
The game starts out with a colored game field in the game window.
The user can press left and right to move the block back and forth, up and down to rotate the game field, and spacebar to drop the block.
The code and the executable are available at the following link:
Rotris, a simple proof of concept in XNA Game Studio