Facebook Read Eval Log Loop is an interactive environment for exploring the Facebook Connect JavaScript SDK. The SDK is available here.
Make sure you have Node (v0.3.x) and npm installed, and then:
git clone git://github.com/nshah/rell.git
cd rell
git submodule update --init
npm link
spark2 --watch
Then go to:
http://localhost:3000/xfbml/fb:login-button?appid=172938186058874