I was able to get a Rails app up and running within 20 seconds of downloading this binary. This is on my work laptop that doesn't even have Rails, homebrew, rvm or RubyGems installed. Very cool.

I'm proud to have backed this on Kickstarter. Best $20 I ever spent. Thanks Yehuda!

Edit: I should add that getting Rails up and running from zero is still quite painful for beginners. I've seen it when helping others install Rails for the first time.