One of the children received a SkyRail marble track for Christmas. These are wonderful toys that are powered by thinking! It was a real popular toy with all the children! Dad helped them learn how to put it together.
Several days later, we were in Target and found several SkyRail tracks on clearance. I wish we could have bought all of them, but we did get two. Now all of the children can build! Here's what is gracing the library right now.
What a great tool to learn physics concepts: cause and effect, speed, friction, inertia, etc. and have a lot of fun at the same time!