Time Based File System

I was playing with Evernote. I am fascinated with the ability to search documents based upon time. One can see this functionality in Office 2003+, where grouping allows emails based upon today, a few days ago, last week, last month, etc. While one can do a search or sort, it would be nice to see a grouping of items, so one can see the result of "I thought I was working on x a week ago..." and easily look it up.