One project had trouble installing the Rails 2.3.3 with the most recent version of Rubygems (1.3.5) on a Gentoo box (EY Solo instance). Installing the gem on an OSX box worked fine with the same versions. No obvious solution presented itself, other than to roll back to Rubygems version 1.3.1.
If you do update your Rubygems version to 1.3.5 and you use Geminstaller you must update your Geminstaller gem to 0.5.2; Rubygems made some changes that break Geminstaller’s implementation. If you use an older version of Rubygems then keep using Geminstaller 0.5.1.
One project wanted to find all places where they needed to escape user input on their site, so they injected
<script>alert('foo');</script>into every text field in the database, ran through their site, and looked for every place that a pop up box appeared.