At long last, Address Book Dates works again! Sadly, no, not on Mac OS X 10.6 (Snow Leopard). Apple never fixed any of the bugs I reported. But now that Mac OS X 10.7 (Lion) has hit the streets, I managed to get everything up and running once more.
As always, you can also use the iOS counterpart, Dates, if you have an iPhone, iPod Touch, or iPad.