Craig, take a look at Owncloud as a calendar/contact/file server; I hook up DavDroid and CalDav Sync Adaptor to that (have had this set up for a month or so now since I wiped my phone, installed CM and shunned Google), with no significant issues so far. DavDroid does both contacts and calendars, but it displayed all my calendars in one colour (may've been fixed in a recent update) which is the only reason I grabbed CSA instead.