Rails Envy (the "I'm xxx", "And I'm Ruby on Rails" people) has
produced two Envycasts on Ruby 1.9, featuring me presenting new 1.9
features, some tips, a few pitfalls to watch for if you're migrating
code, and general 1.9 literacy.
You can get Part 1 and Part 2 separately, or get them together for a
discount. It's a great way to get your bearings in 1.9 and learn some
cool and useful things about strings and encoding, arrays, hashes,
enumerators, the new block variable rules, and more.
More info at: http://www.envycasts.com