Most should know about the malicious gem(s) uploaded to gemcutter.org; if so you’ll notice you can’t search for gems via the website.

I advise everyone to downgrade to jquery-rails 2.1.4. Version 2.2.0 has caused all kinds of problems for me. I couldn’t get my javascript to work inside a facebook canvas app I am developing, and another strange bug was found regarding jquery.validate.

So put this in your Gemfile:

gem 'jquery-rails', '2.1.4'