I know that tryruby is based off of why's guide, but here's his great book in HTML form

http://mislav.uniqpath.com/poignant-guide/book/chapter-1.htm...

I'd also recommend Zed's book as a place to do some exercises. It is pretty much a straight port of his Python book, so you won't learn the idioms, but it's still well structure

http://ruby.learncodethehardway.org/