> Is anyone here using WEBrick on a production site?  Do any of the
> famous Rails sites out there use it?

instiki.org and wiki.rubyonrails.com both run WEBrick and are doing 
fine.

> I've heard that FastCGI is probably the best option for deploying a
> production Ruby-based website.  Unfortunately, I was betting on using
> WEBrick for my backend (Apache would still be in front), and it would
> be quite disappointing to find that it's not up to the task.
>
> So, any anecdotes of successful and significant WEBrick deployments
> out there?

There's nothing preventing you from doing that. If WEBrick is fast 
enough for your site, then by all means go for it. But if its not fast 
enough, you'll need to get on FastCGI.

I'm not sure why you wouldn't want to use FastCGI if you're using 
Apache anyway? Then you wouldn't have to play proxy either.
--
David Heinemeier Hansson,
http://www.basecamphq.com/   -- Web-based Project Management
http://www.rubyonrails.org/  -- Web-application framework for Ruby
http://www.loudthinking.com/ -- Broadcasting Brain