Very seldom and in my case only when you are over 2500 points (though i think it's more dependend on a lot of action on the playing field for an extended time) some blocks instead of falling seem to explode (it looks like they come flying towards the camera while their triangles are separating). After that the game just hangs (i.e. no new rows, no garbage, but one doesn't time out either). The game can be stopped with the esc-key though, so it's not really dead.
Btw i have an nvidia GeForce4 card with the nvidia 6111 drivers on Debian GNU/Linux.