'Growing Ribbons'?
 

We've all probably seen them, but I want to know how to make them. I am wondering if there's an easy way to make sort of a curvy tube that essentially 'grows' along a path. Here's an example of what I'm talking about:

http://www.templatemonster.com/flash-intro/7807.html

If anyone could outline a good method, I'd be really happy. :)

Thanks.

- Cole