Lightris

Description of Lightris program from Softdepia.com:

Lightris is an addictive action game. Bricks of various forms fall from the top of playing area and your task is to destroy them. Just try to form a solid row of blocks across the playing area and the row will disappear. Falling bricks can be rotated, moved horizontally or dropped down.

Lightris is a "Free to try" program. You can download and try it for an evaluation period.