Rent it, enjoy it, but you'll beat it in a matter of hours
The problem is, after playing for only a few hours, you'll have seen everything the game has to offer... except, maybe, for 2 or 3 microgames. There's a ton of variety, but each original thing literally lasts only for a few seconds. You can replay sets of levels again once you've beaten them, but the only benefit to this is unlocking more games. Once you've beaten a level, it seems so much easier if you play it again that it gets repetitive.
There's a multiplayer mode that you unlock once you beat the game, but it doesn't support more than one controller. That means that you have to hand off the wiimote to the next person in order to keep playing the game, which can be annoying - specifically if you want to slip on the wrist strap every time, or if a person is being a poor sport and keeps the controller from you.
In conclusion, the game is fun while it lasts. However, the difficulty (easy) and the game length (really short) make it hard to get your money's worth if you buy it. Rent it first, and if your friends all really like it, get them to pitch in on buying the game. You'll probably end up kicking yourself for spending 60 bucks on a game that lasts an evening.