I have a lot bookmarked on github, these are mostly libraries.
https://github.com/coolaj86/futures https://github.com/substack/node-seq https://github.com/marcuswestin/fun https://github.com/creationix/step https://github.com/chriso/chain.js https://github.com/substack/node-chainsaw https://github.com/caolan/async https://github.com/kriszyp/promised-io https://github.com/kriszyp/node-promise https://github.com/technoweenie/node-chain-gang https://github.com/creationix/do https://github.com/willconant/flow-js https://github.com/creationix/conductor
Some branches of CoffeeScript are also trying to ease the pain. Defer keyword didn't make it into CoffeeScript main. My impression is CoffeeScript makes callback hell less ugly anyway, so there is less need for adding a complex language feature that generates unreadable JavaScript.