No, this is not a real Sinatra error :).
This is the personal homepage of Elad Meidar, a web developer and an entrepreneur specializing in Ruby on Rails. I hang around in Israel, and i am currently having the best time of my life over at Fiverr.com
I am a proud member of RailsBridge, Helping new Rails developers get into our world and also contributed a few Patches to the Ruby on Rails core.
I came across during my never-ending quest for Rails and Ruby related websites, in this cute site (re-design, fast) at Ruby Plus.
They composed over 90 (to this day) screen casts about ruby and rails, including some Rails 2.0 roundups, Ruby metaprogramming and so on.
use it, bookmark it, watch it. (and get the feed too :) ).
You're seeing this error because I think it is funny.