Video games, more specifically, 3D video games. You could query the API, if they've got <50% battery left, adjust the draw distance to decrease rendering for l

Video games, more specifically, 3D video games. You could query the API, if they've got <50% battery left, adjust the draw distance to decrease rendering for longer play. It's very niche, but along with video games, i'm sure some novel hacker will find a use for it!