CalDAV Clients/SOHO Organizer
From DAViCal Wiki
This is a Mac only client which is a proprietary program you have to buy. They had a free download though, and I had a Mac for a while, so I made it work OK with it.
SOHO Organizer has some bugs around calendar creation but there are hacks in DAViCal 0.9.3 to work around them. It should work fine.