I'm always wanting to learn new Ruby tricks (what's in the name) and I stumbled across a very fine list of Ruby awesomeness which is called "Awesome Ruby", you can visited it here: http://awesome-ruby.com/. Just wanted to let you guys know about this thorough gem list.
If you're a senior Ruby developer you properly already know this list, if not it is a very great resource to start when starting a new project!