Just taught my 9-year-old nephew Power Grid, and we played a full game, and he stayed focused enough to beat both his grandparents (although I powered 18 cities, so he didn't win his first time).

I was apprehensive and wanted to start him on Carcassonne or Settlers, but he insisted on Power Grid, and it worked out well. Now he wants to try to get another game in tonight.

"A massively multiplayer game built on your social networks.

GXC is a team-based locally social online sport that revolves around your connections, location and interests."

OK, they can probably explain themselves better than I can, so I'm just going to link to their website and their blog.