WEBrick is doing a reverse DNS lookup on connecting IPs by default. In other words, it's trying to see if your IP address is associated with a domain name. This is unnecessary and takes too long, so you can disable it.
Open the file "l/ruby/lib/ruby/1.9.1/webrick/config.rb" and locate the line with ":DoNotReverseLookup => nil".
Change nil to true.
Enjoy!
