svn co http://svn.gna.org/svn/bongo/branches/sundial/
And then install how one normally would from source. To try out the CalDAV support, you must be running standalone — Apache will simply not work at the moment. Point your client at:
You should be asked for username and password, but the auth system is a little broken at the moment. It is next on my list of things to do with Sundial, and hopefully I’ll commit a fix for that tonight, but I might not have time..
Remember that this is three or four days old and not only will it have bugs, but if you glance at the code, there are many TODOs floating around, so this is very alpha quality software. With respect to CalDAV client support, I’ve done most of the testing on Mozilla Sunbird and in my opinion that has the best CalDAV support, but Evolution should work (it did last night)! Come find me on IRC if you have any questions.