Good 2 player coop DS games?

I just bought a DS for my girlfrend a few weeks ago, and after watching her play I bought one last night.

My question is, are there any good DS games that we could play together in a coop senario? Not just vs...

The games I bought her so far are :

New Mario

Zelda

Kirby

All those games have a 2 player option but they are all vs.

Any good RPG's out there that are 2 player, and would I need to buy 2 copies to do it?

Hahaha ya i would really like to know.

I want to get a nice few games that we could play together. Puzzles, action, rpg. No shooters unfortunatly she really doesnt like those kinda games.

Im guessing its this one right? Do i need to buy 2 copies or just 1?

you got it right

and no you only need 1 cartrage

Ah nice thanks a lot.

Also would you know any good puzzle games?

Contra 4.

Be warned that its insanely hard.

A good muliplayer game is Mario Kart man! Who doesnt want to race around and beat each other with shells and banana's :) One of my favorites and u DONT need two games, only if you both want to pick ur character