Trello

http://trello.com

http://en.wikipedia.org/wiki/Trello
“Trello is built on top of MongoDB, Node.js and Backbone.js”

http://www.bothsidesofthetable.com/2012/08/14/trello-versus-asana
http://www.attorneyatwork.com/asana-vs-trello-checklist-collaboration-tools-compared
http://www.quora.com/Asana/How-does-Asana-compare-to-Trello