Org-mode is part of the emacs text editor. It is a versatile ToDo-list manager, project planner, life manager. Org-mode has the ability to show information grouped by day, week, month or year. I added grouping by quarters to this list.
My patch is accepted and is part of org-mode since the 7.4 version and is in the general emacs distribution since version 23.
My patch can be found on the org-mode development mailinglist.