To be honest, every minute of my free time I spend on reading books and learning new things so I don't have it so much for open source projects. But I'm sure I will expand this list soon :)
Here are some of them:
Magallanes - this is not my project but so far I am the first official contributor here. Simple project for application deployment. Awesome alternative for people who don't know Ruby but want to deploy their applications in Capistrano way. Configuration is based on YAML files, custom tasks can be written as PHP classes. Big props for Andrés Montanez for this.
Symfony2 VHost generator - project under heavy development. Symfony2 bundle for configuration-based Apache2 virutal hosts generation. Honestly, there is still much to do to I haven't use it yet in my projects.
EventEmitter.dart - ready to use project. When I started to develop one of my applications in Dart I missed EventEmitter class from node.js. So I've created one, voilà!
SocketIO.dart - I am not sure if I should add this to the list... Quick fail project. I missed SocketIO's abilities in one of my projects that had ready frontend with socket.io-client. SocketIO is awesome lib, but it handles websocket in specific way (like event types or structure). I wanted to literally rewrite socket server to Dart but I gave up quickly. I should close this project... what a shame.