About 8 months ago I started working on a networked family calendar application. I heard about four months ago that Google was working on thier calendar application. Then a couple of days ago I heard that Google had released their calendar. It is very nice. I especially like the way it handles string parsing so that you can enter entries quickly. The sharing is pretty good too. If I have any criticism, it is that it isn't seamlessly integrated into their other applications, but I'm sure that's coming. I know that when Google moves into your neighborhood, you should move out, but I just can't stop working on my calendar. I really think that some of what is in my calendar is as good or even better than what is in Google's.
My calendar can be found at www.familycal.com. The cool things about it are that it operates on the principle of a family initiator. The family initiator can add their sub-unit to another family, or remove them from the family. The privacy settings allow you to determine what is visible to the entire family, your immediate family, or just you. Immediate family is determined by whether or not those people have signed up based upon your invitation, or if they are a part of another family network that you have joined.
It currently allows you to add RSS 1.0 feeds, and has an ajax driven to-do list. I think that building it is a lot of fun, and I definately learned alot about domain modeling in the process. If Google Calendar runs mine into the ground, so what. I know that I have a good product!