I remember when you could run Doom over a lan. You'd set one monitor to be your forward view, and then set two more monitors to be your left and right views.

http://doom.wikia.com/wiki/Doom_networking_component

> The higher level d_net.c file contains the system-independent portion of the networking code. The code has separate concepts of node and player: a node is simply a computer connected to the game. Each player has a corresponding node, but a node does not necessarily have a player. This was used to implement the "three monitor" system which existed in early versions of Doom: the "left" and "right" screens were nodes but not players.

I only played that way a couple of times but it was fun.