Only good if you play it as a family, but by yourself, don't even bother.
The point of the game is to earn as many prizes for the games as you can. They have games ranging from the Dunk Tank to Minigolf to Milk Bottles. There are several different games, but they get boring quickly and sometimes make you want to throw the Wiimote into the tv.
The only somewhat strong point of the game is the multiplayer. You can have some good ol' fashion family fun when you play this game. That is, when you don't get too frustrated by accidentally pressing the wrong button and having your turn go without your intention. But, you can have fun with this game, but do it as a family.
Carnival Games is a creative idea that is brought down by boringness and lack of any motivation to complete it. But it can be fun as a family. But I would not recommend this either way.