A Webring is a way to group sites with a similar
interest together in a "ring". Links on
each page in the allow you to move from one site to
the next, allowing one to (eventually) traverse the
entire ring and end up where they started.
The AD&D Ring is a webring set up for fantasy
and AD&D related sites.
Take a look at the AD&D
Ring homepage, the About the
AD&D Ring Page or the What
is the Webring information page.