How old are the girls again? I got the demo for Kinectimals and mine loved it. As far as regular games go, just look at the all time scores on metacritic.com and see what is up your alley. Depends on whether or not you like shooters. There are a ton of good ones, but you may want to focus on sp ones where the gameplay is longer or co-op for you and your son. Gears 2 is a good one for horde where you guys can team up and play the missions together and should be on the cheap. Also, for the Kinect, Kinect sports are fun for the whole family, though they do have a recognition issue at times. You can even send out challenges on the 2nd one without worrying about pausing it... though, I'm not sure that the price is down on either.