It's out folks. If you haven't tried it yet. You need to: http://calendar.google.com/
Two thoughts:
1. Google needs better privacy policies (and I don't mean the written one).
2. The Open Source world needs to get its act together. We're too splintered, disorganized, and capitalistism-fobic. These are fixable problems: use better licenses (BSD, MIT, Apache, MPL), use and promote open standards, and share between projects wherever possible.
That's all very Google Calendar related in my mind... :)