Originally Posted by zhian
For games a bit more "out there" in concept and execution, try the ones mentioned in this article - World of Goo, Machinarium, and Braid especially.

Zhian,

Just to let you (and everyone) know...We downloaded free demos of Braid and World of Goo and the kids love 'em! Both require some great strategy and higher order thinking skills. Braid is very challenging but beautiful and very cool. Goo is challenging and cute. Thanks for the suggestions. We would have tried Machinarium but it was not available.