Several new crazes have come about lately on this board...
The first of which was Tetrinet. (isnt it fun!)
The second of which was Liero. (yea!)
Now....prepare youselves....for #3...
3d Tetris!
http://www.xdsoft.com/3dblocks/
Too bad its not multiplayer.
I saw one that used D3D and it was multiplayer on download.com, but the link was bad.