This week's book giveaway is in the Mac OS forum. We're giving away four copies of a choice of "Take Control of Upgrading to Yosemite" or "Take Control of Automating Your Mac" and have Joe Kissell on-line! See this thread for details.
Ludicrous is a just-in-time compiler for Ruby 1.8 and 1.9. Though still in the experimental stage, its performance is roughly on par with YARV (better in some benchmarks, though that may change as more features are added). It's easy to use:
# (or Ludicrous::JITCompiled)