Windows: Nemo Documents indexes your files into a calendar view, based on when you last modified those files. The brilliant interface and tagging capabilities make it easier to find and manage your documents (including Google Docs), and also track your work history.
The free Nemo Documents application supports many different file types, including Office files, images, videos and Google Docs. The program also integrates with Windows Desktop Search so you can pull up files based on phrases within the documents, file types and modification dates.
The calendar view is a very intuitive way to manage your files, since you can quickly find or see what you were working on two weeks ago or on a specific date. You can view files by day, week, month, year or in a list view, and also add in your Google Calendar events.
Other highly useful features of the program are its customisable filetype filters, label tagging, and the ability to open files directly from the grid. (Note: I did run into a few instances where some linked Google Docs returned an error in the browser when trying to open them, but otherwise the file opener worked fine.)
All in all, it's a great way to manage and view your files. For people who have to fill in timesheets or invoice for their projects, Nemo Documents may be even more useful.