Which accessories you need depends on the game that you want to play. The Wii Remote is the basic controller that connects to the Wii. Some games can be played with the Wii Remote alone, such as New Super Mario Bros. Wii. The Nunchuk is an add-on for the Wii Remote which has an analog control stick and more buttons. Some games require it, such as Super Mario Galaxy, but others don't. There's also the classic controller, which connects to the Wii Remote just like the Nunchuk and is needed for Virtual Console and some WiiWare games purchased from the Wii Shop Channel. As for games, it depends on the age group and type of games the kids like. The most popular family-friendly multiplayer games (in my opinion) are New Super Mario Bros. Wii, Mario Kart Wii and Smash Bros. Brawl and based on the limited info you gave, I am recommending those three games.