Mario Kart DS is a game with both single player, and multiplayer modes. It can be connected to the Internet, so it is an online game. The following is a list of friend codes. To play with someone using Mario Kart DS, you need to have each other's codes. To get your own, you must have signed into the Nintendo WFC once. To get it, go to the Nintendo WFC section of the menu, then Friend Codes, and then Confirm. Your friend code will be on the top screen.