Alright, let's do ruby then. I use vim with Ri, Rdoc, and ack-grep plugins (https://github.com/kristopolous/vimbuild) and then use irb with a bunch of extensions (http://stackoverflow.com/questions/2952793/anything-like-bpy...) but there is nothing out there that makes my life phenomenally easy yet (for instance, some really awesome code navigation tool). zsh has built-in autocomplete for ri; try running zsh then do "ri <tab>" (http://qaa.ath.cx/ri.png); that ought to win you to at least having it installed. And yes, you can do "ri XXX#<tab>" for the second level! (http://qaa.ath.cx/ri-kernel.png)

For the record, I do straight ruby; I don't even know how to deploy rails.