This toy may seem to be mainly about RC vehicles, but there is more to it than that. You can get the vehicle kits but you can also buy something called the Inventor's Tool Box which allows you to design your own Rokenbok machine. They have a variety of products available for different age groups, so it's worth looking around the Rokenbok site. A reasonable way to buy it in Canada is to source it from Mastermind Toys (out of Ontario).
I think I have had as much fun over the years playing with marble runs as my kid has. There's just something so satisfying about building something and watching everything happen. You can buy plastic marble runs (Quercetti) or wooden marble runs (Haba). You can even buy marble runs that double as blocks (Cuboro). And I don't believe you can have too many marble runs. We have a Quercetti run as well as several sets of the Cuboro (which was an investment). They use different building principles and require different thinking in terms of construction. The Cuboro is a little harder to find, but you can buy both the Haba and Cuboro sets through The Wooden Wagon (watch out for the duty ding at the door, though).
Cuboro (made in Switzerland) appeals to marble run addicts of all ages. In Europe, there are yearly competitions and you'll notice how many of the participants are grown-ups.
Here's a good visual example of how the run works.
K'Nex is widely available in many different toy stores. It's a great building toy, with lots of flexibility and potential. And most people know about it.
However, if you have some extra money laying around (say, you haven't spent all of the year's learning investment), you may want to purchase one of the educational kits you can get through Spectrum, such as the Amusement Park set or Roller Coaster Physics. Or the fabulous Ball Factory.
I've already gushed about Lego under the mathematics section. However, if you are looking for that extra bit of "science" to entice your child with, you may want to consider:
Lego Technic - lots of gears and pneumatics and motors, just read the description of the product so that you get what you are hoping for.
Lego Power Functions - these help bring your Lego creations to life; usually they support a kit, so you'll need to figure out what matches with what.
Lego Creator - There's only the ferris wheel or drawbridge available now, but it's worth it to keep one's eyes open for new sets. Sets like the Grand Carousel also use gears and motors.
Lego Mindstorms - I can only say good things about Lego Mindstorms. Lots of hands-on physics is required to build robots that will perform tasks. I'll get into the "computer science" of it in an upcoming post.
Lego Dacta - These sets tend to be a little more deliberate in terms of the science learning. You can buy sets relating to alternative energy, pneumatics, and simple and powered machines. A good source for these in Canada is Spectrum Education.
Hydrodynamic Building Set
Okay, this is just too, too cool. Seriously cool. Once you watch the video, you'll want one.
Here's the ThinkGeek write up about it:
Water is everywhere. It covers 71% of the Earth's surface and composes about 112% of the human body. Gaining control over water would be an awesome super power, but for now we are stuck with using science to master water. Good thing someone invented this Hydrodynamic Building Set. It makes science fun again. But this kit isn't a simple connect the dots - you have to do some thinking! Why? Read on!
The instruction manual shows you how the girders connect, how to build the various tanks, and some rendered images of completed projects - but not step-by-step. Your entire model gets built up from the bottom of the carrying case, which acts as the water reservoir and also has a special footing to be the structure's foundation. Level by level, you build your support frame and add your tanks. Then connect all the tubes, add in the valves, and turn on the electric pump. If you've done it right, you'll have an awesome construction everyone will marvel at (a little food coloring helps). Fail and you're all wet - quite probably literally.
Fischertecnick is a German-designed and manufactured building system. You can use the kits to create projects, or you can branch out from there.
There are several different products available and they have them categorized by age level (which is helpful). It's a different system than either K'Nex or Lego, and is certainly worth looking at if you have a young builder in the house. It seems to be a notch up in terms of construction complexity, allowing for more realistic models. It's hard to find a Canadian supplier of Fischertechnik (so if you know of one, please share!), but you can find some of their robot kids at the Robot Shop. The video is an ad, but it will give you an understanding of this construction product.
Meccano has been around for a very long time... over 100 years, actually. My husband spent many a childhood hour playing with his Meccano set. Meccano has changed quite a bit since then and even has sets for younger kids. If you want something that is a bit more reminiscent of days of yore, you may want to consider a Super Construction Set that allows for more open-ended building and also includes a motor. You can find a lot of Meccano choices through Mastermind Toys.