Unbelievably amazing to be able to shift-click on syntax and jump to the source - even works pretty well in dynamic languages.
I HATE using a Gem then needing to break my train of thought to pull up the official documentation to see what an API interface looks like. Ctrl+click. In and out in 15 seconds.
You just taught me something! I've been using keyboard hotkeys to jump to source. On mac, I can hold down command (probably ctrl on linux) and it lights up like a link, shows the gist, and let's me click to go to source.