When I am home (which never happens anymore, due to unrelated issues), I usually set up a LAN and play Master of Orion II, Descent, Alpha Centauri, or Starcraft with my Mom. She is decent at Master of Orion, but I can take her down quite easily. We are about evenly matched in Alpha Centauri, but I am much more cold-hearted, so I can usually come out with a win. Descent and Starcraft she isn't so good at, but she plays anyways because she thinks that the games are fun.
The games that really interest her are RPGs, but for some reason she has difficulty playing them because she gets lost and can't figure out the controls. That just strikes me as strange given that she can fly somewhat straight in Descent, but I have long since given up on teaching her to play right.
Most of the time, I will just have a friend over and play some GameCube games, or play some PC games online.