Depends on the game. I'd say I have two modes of sitting when programming, one is passive and my muscles ache. Another is active, when I try to use belly muscles (abs?) to keep my posture etc but... When I fall deeply into thinking I will eventually release muscles and feel worse later.
I wonder if there could be an application that would encourage active sitting
This is what I was thinking about too. I thought that "Active" sitting was going to be something about making sure you're not slouching, but rather adjusting yourself every so often to make sure you're sitting up straight instead of slouching off the chair.
I wonder if there could be an application that would encourage active sitting