Radius is "powerful tag-based templates," or in layman's terms, it's safe templates for Ruby that look like HTML.

<ul>
  <g:stooge>
    <li><g:name /></li>
  </g:stooge>
</ul>

Radius 0.5.2 kind of sucked though. The more params you had on tags, the slower it got:

(left column is number of params)

Since our big app at work uses Radius not just as user->system templating code, but as system->system processing code, we were generating Radius tags with forty params, which Radius's regex would have taken about eight months to chew up.

So I rewrote it, in Ragel which is just flat out nicer. Instead of dealing with a regex, you're describing a state machine; they both get turned into NFAs in the end.

Looks like the gem hasn't built yet on github, so if you want it you'll have to build it yourself (it'll be bkerley-radius-0.6.0 when it does go). I'll try to edit this post when it's available.