I remember the best multiplayer DOOM experience was got using a little hacky IPX/SPX over parallel driver. When my friend would bring his rig over to my place to play we always spent way longer getting stuff to talk to each other than actually playing. Good times.
IPX over parallel is true dedication! We at least had network cards so the only difficult part was remembering to put termination in the right places on our 10Base2 ethernet.
