We are going to deploy a Wiki system for a medium load website. Any
recommended Ruby options?

The Wiki doesn't have to be feature-rich. It can be simple, but should
be elegant and easily extendable, as the people who are going to use
it are mostly hackers.

The only special requirement is that it would have decent bidi support
(for Hebrew pages). But if you know a good Wiki codebase answering the
above description, we might extend it to support bidi by ourselves.

Cheers,
-Alder