A reference to use when you get tired of decorating your homepage with nothing but primary colors - but remember that most of these are not browser safe.
The webring system that you probably haven't heard of, or something very much akin to a webring system. You can't create your own ring (or "train" to use their terminology) yet, all rings (yes, trains) on their site being run by the staff, but you can submit your sites to the rings already present.