I browse through a few news source throughout the day, and occasionally come across some real gems. Today's activities lead me to "why's (poignant) guide to Ruby". Here is a FREE online book that has a fun and engaging style to teach you about Ruby. I have taken the time to read through the first few pages, and I like the approach thus far.
The page linked to above does have an option right at the top to download the entire book as a PDF, or you can read through it online by clicking the "open the book" link to the left.