If some of you guy's want a fun challenge, try building some slots out of old hard plastic pull back cars! Zee toys made a bunch of them in the 60's, and still do. they can be had very cheap on ebay, and are often available in lots real cheap. I just got these the other day, and have built a few of them over the last months. Some are fairly accurate representations of the real cars, some are not, but can be made to look good anyway. They even pop up at the dollar stores quite often. Try em! you might like them!
These are a few I have built from similar Zee toys pull back cars.
Bob