just in case you're playing around with Ruby - and you do not have the famous pickaxe book at your fingertips (either you tried to save some money - which was a bad idea, or your so-called friends never gave that cool bunch of paperized knowledge back to you...):
Try the (german) tutorial - well done Sascha, ruby-in-small-doses, good content, digestible.
Our cat just took a nap on top of my pickaxe-copy... so I needed some ruby-centric diversion :-)