[Pix]

For my other classes, which are a bit more advanced (ages 3-5) I'm trying to think of activities/games to teach them classroom commands (ie raise your hand, point to..., sit in a circle, stop, go, etc.)

For this you could play a version of grandmother's footsteps.
All the children can be at their desks except one at the front facing the board. You give the commands and the class do them, but at any time grandmother can turn round - at which point the class have to freeze and grandmother has to catch someone moving - who then becomes grandmother, or who sits down for one go, but can stand up and carry on playing the go after that.

You don't want to be swapping grandmother over all the time or it'll get boring and be too slow.