There is one game played online these days that appears much like Tetris, but with a slight variation. It is called bubble shooter, and the game can be quite addicting, as attested by a few bloggers.
Basically, the aim of the game is to shoot at the bubbles coming down on you. At this point, the game appears very similar to the Tetris where you try to make use of the blocks coming down from above the screen in order to create the image of a building.
The difference begins when you start shooting at the bubbles. Hitting at least three similarly aligned bubbles on a consecutive basis will cause the bubbles to pop, and a score will be registered under your account.
Simply make use of the mouse when shooting at the bubbles. In case you are having a hard time hitting the desired ball, there is a portion in the screen where you are able to see what the next bubble looks like. This should help you out greatly in your scoring while enjoying bubble shooters.