Very cool Mutiplayer Tetris game found: Blockz. It's free and has many different game modes. The touch screen element is well implemented (handy if you want to move a block very quickly to the right place).

Graphics look very neat. Rating is 4.9/5 stars so give it a try I would say

https://play.google.com/store/apps/details?id=com.relaxfactor.blockz

Thanks.I just played it with my friends and it is really fun.

Hey I've been playing this for a while and absolutely love this game, def worth downloading

I contacted the developers and the old link does not work anymore, this is the new one!
https://play.google.com/store/apps/details?id=com.modernarts.tetroid