Grand Theft Auto, Jr.
Let me get the negative stuff out of the way first: the only reason this game loses points is because it keeps freezing, a lot, and I hear a lot of other people have the same problem, so it can't just be my copy.
Okay, now that that's out of the way: Bully rocks. It's everything every little mischievous kid would have wanted to do when faced with prudish authority, asinine bullies, and antagonistic prissy pricks like the rich kids. For the kids whose parents don't condone the uber-violence that is GTA, this is a heavenly alternative. It's fun, it's big, it's colourful, it takes place in the GTA universe with the same style & controls, and it's packed with so many hilarious characters it has every right to have its own comedic HBO spin-off. Skateboards, stink-bombs, swirlies, graffiti...this is honestly a better Bart Simpson game than any game that actually lets you play as Bart Simpson.
