Does anyone knows how to force WEBrick to process more than one request at a time? I'm using some Ajax on my page for long running database-related tasks and I can clearly see the requests are being processed in a pipeline.
If you use JRuby, check out the GlassFish gem (stripped-down GlassFish server in gem form), the Trinidad gem (same thing using Tomcat), or various other options like warbler (produces .war files you can run directly or deploy to any app server). JRuby is the easiest way for sure to deploy a highly-concurrent application on Ruby, and makes the C Ruby options look rather primitive in comparison.