I was working on a project very similar to github.com/nex3/jabl in the months running up to RubyFringe.
Then I saw Hampton's presenation. Oops.
I pulled it out of github.com/collin/lucky7 and stuck it here.
And hacked around a bit, removing some features, adding others.
Check it out:
(add github to rubygems) gem install collin-fold git://github.com/collin/jabs.git cd jabs
Look through /examples