Wii Sports is a very slick package, and is a great tool for showing non gamers just how cool the Wii is.
You get bowling, baseball, tennis, golf, and boxing in Wii Sports, and I'd say the order of most enjoyable to least enjoyable would go: Tennis, bowling, golf, baseball, then boxing. On the plus side, they all work and are all fairly fun, but on the downside, the controls sometimes seem a little buggy, particularly when you are putting. This is a minor detail though and doesn't detract from the overall great impression this game leaves you with.
I actually love the graphics of this game. Sure, they could have gone further with the Wii hardware, but it really does have a very clean, pretty look. I had a large crowd over to check this game out, and even though it's no gears of war, everyone kept complimenting the graphics, and how nice and pretty it looked. The golfing in particular is quite pleasant to the eyes.
Wii Sports truly shines, and has plenty of cool features, such as how the controller makes sounds that go with what's happening in the game (you hear a satisfying "bop" when you hit a ball in tennis, for example), and how you can place Miis right into the game.
All in all, Wii Sports is an excellent game with few flaws, and should be played by everyone, everywhere. Do yourself a favour and give this game a try.