Ok...I've had a few days to catch my breath...and have looked at iCal and a rewrite that would either 1) take advantage of the iCalendar spec and at least support import/export or 2) base the entire DNN Events module on the RFC2445.  Thoughts? 

For #2, the entire datastore would be based on RFC2445...the only bad thing about this would be:  if it ain't in the spec, it don't get implemented...say bye-bye to things like "paid event enrollment"..."automated notifications" aren't supported either... I don't think this would be acceptable...

So, I believe what you guys really want is RFC2445 support with extensions.  Still not sure how to do this...  First, I have found what looks to be a good open source (kindof) implementation of RFC2445.  It's called: DDay.iCal by Douglas Day...at: http://www.ddaysoftware.com...  you can email him at: doug@ddaysoftware.com... I have and am trying to convince him to donate time and his source code to the project.  You can download the .NET 2.0 version of his project at: http://sourceforge.net/project/showfiles.php?group_id=187422&package_id=218792&release_id=487917

If Doug is not interested in contributing the source code to the project...well...is anyone else willing to sign up and donate code/time?  If interested, let me know.  I too think this is important and have emailed him...  I believe this project would give his effort more visibility and credibility...after all we do have a few users of DotNetNuke...

I've seen remotecalendars as well.  This is not an implementation for reading/writing ical data...but instead an Outlook specifc implementation.  Would not help us on this project.

Yes.  It is not supported by most other Calendaring Software, including the iCalendar Spec.  We will only support a single calendar include...so will support multiple calendar includes...but not unlimited/recursion.  This would be abused, cause excessive resource consumption, and ultimately lead to an unsupportable product.  Although we want a lot of features, I don't think anyone wants a product that is unreliable.