After updating to rubygems 1.2.0 I've noticed that my mongrels started returning the following colorful error on every XHR load, i.e. all AJAX requests fail but regular page loads are fine:
Mon Jun 23 23:39:15 -0400 2008: HTTP parse error, malformed request (127.0.0.1): #<Mongrel::HttpParserError: Invalid HTTP format, parsing fails.>
Given that rubygems was the last thing I updated, I figured I'd try reverting to the previous 1.1.1 release using the following steps: