We use a few options, because we are very familiar with indoor recess. Here are some things we do: four corners, heads up seven up, GoNoodle, and simon says. You could also create your own “cake walk” like game with numbers, shapes, addition, letters, letter sounds, cvc words or sight words. Make them on laminated paper, place on the ground and have the kids walk around to music. When the music stops say a number, shape, letter, letter sound, cvc word or sight word. Those standing on that word stay and the rest sit down for the next round. Now, I would do 3 or 4 choices of each that you pick, so that a third or fourth are left standing. You can adjust it to fit your liking.