Wii Sports (Wii)

Wii Sports is bundled with the Wii and is a brilliant demonstration of what the Wii can do. The games aren't graphically stunning, but the controls are so intuitive that people of all ages have been playing tennis or bowling after a couple of minutes practice, and everyone seems to find something they like (Tennis and Bowling are the most popular to play with Boxing being the best spectator sport).

If Nintendo ever start to sell the Wii without Wii Sports bundled then always spend the extra money needed to get Wii Sports included, you won't regret it.