NameURLMemo
osmushttps://github.com/borismus/osmusUses Socket.io
nexyhttps://github.com/majimboo/nexyUses TCP
Maplehttps://github.com/bonsaiden/maple.jsSimple, event based Multiplayer for Node.js , uses websocket
POMELOhttp://pomelo.netease.com/index.htmlMore complicated there's an online demo:http://pomelo.netease.com/lordofpomelo/
derbyjshttp://derbyjs.com/Has MVC concept