I tried to get an overview of calendaring but got an headache instead.
There are several authorative documents about getting iCal to work in RDF, but the schema is not consistent and some use other dialects, so pity me.
the mailing list
the good presentation
this is the official test-case collection
the example by Masahide Kanzaki
some of the cases use other ways to note dtend and dtstart, uff.