Advance Wars: Days of Ruin

Like Heather Locklear or old cheese, the Advance Wars series of games just keeps getting better with age. The turn-based-strategy action—you go, then the computer goes, then you go, etc.—sounds like it's about as fun as doing your taxes, but in practice, you'll be sending your eerily cheery enemy troops to their glorious doom, and you'll feel pretty fucking good about doing it. With a lengthy single-player campaign, plenty of optional side missions, and the ability to make your own maps modeled after the final battle in that one Mel Gibson movie where he wears a kilt and paints his face half blue, this cart will be snuggled up inside your DS at least until WW III.