Robin Paul Weijers aka Mr. Domino, the founder of Weijers Domino Productions, is now selling dominoes that are about as close to the ones used for his company's world record attempts as possible.
The dominoes are made of solid plastic, and come in 11 different colors. There are several sets to choose from, each with different amounts of dominoes, and "extensions" so you can get only the colors you need.
These sets include nearly identical camel back stairs, elevators, and loop-de-loops that I used back in the 1980's, but several pirate themed products feature some new tricks.
Domino Rally is a good, inexpensive introduction to the hobby of domino toppling. From my own personal experience, it taught me the importance of patience, how to incorporate stunts, and the process of trial and error.
Buckets of Dominoes
You can find colorful wooden dominoes at various educational supply websites. They are usually sold in buckets and include several double-six sets. You can get 168 to 840 dominoes in six bright colors.
These appear to be the same dominoes used in an episode of "Malcolm in the Middle". Dewey was able to set up a pretty sweet course, so I'm sure you can too. :)
You can buy buckets of dominoes here and here, just to name a couple.
K'NEX
They may not sell dominoes, but K'Nex Industries does produce construction toys that have proven to be very useful for us. They easily snap together to create simple machines like levers and pulleys, and motors can add even more dynamic elements. You'll see K'NEX in a bunch of photos on this web site.
Bulk Dominoes
Does your company offer bulk discounts on large purchases of dominoes? Or are you a toppler who knows of a reliable supplier? Just send me an email so I can help spread the word. There are many domino topplers out there who will give you their business!