Integrated Project Manager (IPM) is a chrome extension that integrates with Google Calendar and Tasks to help you manage your projects.
It is not yet a full fledged Project Management system, but it will get there eventually. Once you install the app you can right away start creating the current projects you are working on and then add milestones and todos so as to easily break down the work.
Projects and Milestones are added to your Google calendar. Projects are added to Google tasks as a task list and each task list will contain the project's milestones and todos.
The application works well both online and offline. However, for now, any data added while offline will not appear online. IPM will get there one day, just not now.
Kindly go through the Help Section in the app to get a better understanding of how the app works.
The app is still in beta. Although your project details will be saved in your Google calendar and Tasks, upcoming versions of the app will not be able to use the same data. So just test it out for now and let us know your experience.