These DevX articles are also a good introduction to the language:
Ruby—A Diamond of a Programming Language, Part1:
http://www.devx.com/enterprise/Article/30917/0
Ruby—A Diamond of a Programming Language, Part 2:
http://www.devx.com/enterprise/Article/31197/0/page/1
It's worth noting that the Part 2 sample application (stock quote
screen scraper) doesn't work. I have an updated version of the screen
scraping component, but anyone with a good grasp of HTML and regular
expressions should be able to quickly figure out what the problem is.
I also tried this interactive Ruby tutorial, which gave a nice
introduction to the language. I think it was created by the author of
"Why's (Poignant) Guide to Ruby":
http://tryruby.hobix.com/
(This tutorial can be accessed from the Ruby website)
As a side note, this DevX article, though acceptable, will cause a lot
of frustration. The author is very inconsistent with the use of
parentheses in method definitions/calls and doesn't explain very well
how to put together a refactored version of his "application launcher"
program:
http://www.devx.com/RubySpecialReport/Article/34502