My company also open sourced our time tracking application (it can do more, like vacation requests and invoices). Right now only the backend API is open source, you can find it here [1] and documentation here [2]. It is a REST API secured via OAuth.

In the next few weeks we also want to open source our main client application, an AngularJS app.

It is probably a little too much tailored to our needs to be used somewhere else.

[1] https://github.com/techdev-solutions/trackr-backend [2] http://techdev-solutions.github.io/trackr-api-documentation/