3. "Pokémon" (franchise)

Release date: September 28, 1998

Platform: All Nintendo platforms, particularly portables

Buy it here.

The game is simple: The world is inhabited by colorful animals — monsters, really — that you can capture and keep as pets and use to fight other owners, called "trainers." Your character travels from town to town, meeting people and running into wild Pokémon along the way. The goal is to build the best team of Pokémon possible, so as you challenge other trainers, and bosses known as "gym leaders," your Pokémon get stronger, you earn badges for your achievements, and you can brag to your friends and rivals that you are "the very best that no one ever was."

Pokémon is the second-most successful and lucrative video game-based media franchise in the world, second only to Nintendo's Mario.