rack-noie6 does everyone a favor: it shows the way out of your website to poor souls out there using Internet Explorer 6 (or a user configurable minimum).
gem install rack-noie6 require "noie6"
use Rack::NoIE6, redirect: "/noieplease.html"
the above will redirect to a page noieplease.html in your website. You can redirect to a URL as well, like so
use Rack::NoIE6, redirect: "http://slashdot.org"
or let the default kick in
You can even specify a minimum version of IE like so
use Rack::NoIE6, redirect: "http://slashdot.org", minimum: 6.0
The default URL points to Microsoft's IE upgrade page.