Not being a massive console fan, I bought the Wii largely for nephew who is a gameaholic. Whilst buying the unit, we had the chance to get three free games. The kids chose Spiderwick chronicles as one of them - they liked the film you see.
The game is tied into the film really cleverly. You play a variety of the characters in the film, one at a time, as the story unfolds. Your objective is to rush around, find/remember things, use them in the right places, fight some trolls, demons, bugs etc.
The integration with the wii and nunchuck is fabulous. A good mix of buttons, joysticks and three dimensonal movement.
The kids loved it, and most amazingly, so do I! Infact, I'm playing it end-end myself, its addictive!