Check out u-appt.el and icalendar.el .
E-Mail from Ulf Jasper
This patch adds support for subdirectories under a main wiki
directory. Subdirectories are recursively added. On publishing, the
directory name is resolved relative to the main wiki directory, then
expanded relative to the publishing directory.
Haven’t added this patch yet. Should think about it more first.
patch 2 changes current emacs-wiki behavior to favor intra-wiki page
names over interwiki names, which may or may not be a good thing.