This may fall under category of "bad parenting" but probably not. I hope not. Just don't tell Lily, OK?
My daughter saw all of the fun her brother has playing Team Fortress 2 and wanted in on the action. The kitchen iMac doesn't play games very well but my PC does. So I set her up on an account there, logged her into Steam and the rest was history.
She picked up TF2 quickly. Then she saw that she could play Borderlands 2, Torchlight II, Portal 2 (is there a "two" thing going on?) and spent hours on the PC.
Her normal activity is drawing on the iPad. She's really good and has developed a real skill. Video games are normally the domain of her brother. But they seem to like playing on the same TF2 server. When they're on the same team she plays the medic and supplies health to the other players. When she's on different teams she plays the scout.
She spent the whole evening playing and I had no clue. It wasn't till I went to turn off the light in the office that I saw her. Her mother would not be happy had she walked into the room.
There is hope that the has inherited Lily's Adult Supervision™ genes. I told her that I'd get a third PC for her, probably from Costco. Her answer?
That's wasteful. I can share yours when you are not using it.
I have no idea where she picks that stuff up. I've certainly never encouraged that sort of behavior.