Our mini humans enjoy things like mario Kart, Wii Sports, the Raving Rabbids series, Kirby's Epic Yarn, Reader Rabbit (good educational game for kids going into 1st grade, but good for surrounding ages too). The various Jump Start games have some educational value.
Some mentioned are just fun (there really is no educational value in the Raving Rabbids games, but BOY are they funny) but the Jump Start and Reader Rabbit are good in that regard.
The Sesame Street games are educational of course, but my kids tired of those pretty fast. Still, they had fun while they were interested, so if you can find them cheap or used they may be worth a shot.