http://en.wikipedia.org/wiki/CalDAV
http://sourceforge.net/projects/rscds/
http://mesh.dl.sourceforge.net/sourceforge/rscds/rscds_0.9.4_all.deb

# Or add to repository:
apt-key advanced --keyserver subkeys.pgp.net --recv-keys 8F068012
echo "deb http://debian.mcmillan.net.nz/debian unstable awm" >> /etc/apt/sources.list
apt-get update
apt-get install rscds

#http://rscds.sourceforge.net/clients.php