For a brain exercises, Letter Quest is good fun for spelling words and has RPG mechanics to make it more exciting.
If you are interested in more historical games, I would recommend Verdun and Tannenberg (PC, Xbox, PS) which are authentic WW1 shooters. Although they don't put as much historical info directly in the game, they are all based on real historical battles, with real weapons/uniforms and the like. Even the name of the game Tannenberg, I was like "what is this about?" and decided read up on it. The battles are quite fascinating to me and they are fun to play as well.