Research on ?open iCal? revealed that: iCal is an Apple program, looks like Apple then released open iCal to increase interoperability. iCalendar is the standard defined in rfc 2445, written by someone from Microsoft and someone else from Lotus.
RDF (resource description framework?) working group http://www.w3.org/2002/12/cal/ are looking into porting iCal to RDF or so it would seem. Does this abnegate the iCalendar, if so should mozilla calendar move over to this new standard?
CalBlog is really suggesting itself to me right now. The point is the facilitation of planning and review of daily tasks. Suggested by 20 minute review mentioned in someone else's weblog.
So basically there is a planning blog that is created at the start of a day, and a review at the end. While writing these blogs, you have access to tasks panels, (today's tasks, rolling tasks) event panels, etc. Blogs are written in a "plain-text" format with ical references and other simple html (href, list, h1-6, li) so you write up a plan for the day, dropping in references where necessary. A clever parser could automatically create tasks as you type, ie "task:" pops up a free-flowing text entry (or task selector) for a new (or existing) task, returns you to the blog with a link to that task inserted when you're done.
Important feature: uses an external apps calendar file. Merely a commentary on the day.
The review can be started as early as is desired in the day.
Potential for dividing the day up into functional blocks eg: time at the office and time at home, each with a separate plan/review pair.