Around 1997 or 1998 my University roommate and I had our Pentiums connected to each other through an ethernet hub. I'm not sure why because (a) neither of us were gamers and (b) we were running Linux so there really weren't any games anyway. We were probably cross-mounting mp3 collections with NFS.
One cool thing we set up was sharing a single dial up connection via routing and NAT. The way it worked was one of us would dial in to what was basically the school-run ISP and the other would set up a default network route that pointed at the machine that was dialed in. We thought this was extremely cool. I mean, both of us could be online at the same time through the same phone line!
I forget exactly how much this dial-in service cost. I'm pretty sure that to buy credit you'd go down somewhere in the bowels of the Math building and wait in line. In my last term of school the house shared a cable modem connection that was online all the time which was truly amazing.