I admittedly tend to shy away from plastic toys, but we recently caved and bought the Perplexus Maze Game, which Laurel couldn't stop talking about after learning about it from classmates. And I have to admit that this game is ridiculously fun. The 3D sphere comprises one long, convoluted maze track including three different entry points -- so, for example, you don't have to start at the beginning if you've already mastered section 1 of the maze. Following the maze requires careful rotation and keeping your eye on the ball.
The maze manages to be challenging (I'm still stuck on track section 2) yet doable (Laurel has already figured out track section 2), and the cognitive psychologist in me wonders whether the lasting enjoyment of this game relates to the fact that you're so concentrated on the track as you rotate that you rarely look at the big picture -- meaning, the maze always seems to look new and different when you approach it. Battery free and super fun for all (even baby Vi likes coming over and rolling it around on the floor...I think the sound of the marble rolling around inside appeals) -- it's a fantastic toy for home and travel.