MobileMe strikes again with this message, conveniently located several clicks down on the Apple support site:
MobileMe members may be unable to access their calendars at me.com/calendar, in iCal, Outlook, or on their iOS devices. Normal service will be restored ASAP. We apologize for any inconvenience.
Translation: Calendar is down, hard. The message you got on MobileMe was “unable to load your calendar” along with a button to send debug information to Apple. Everywhere else it just timed out. Total outage time was around 8 hours, at least for me.
Truly unfortunate since I’m pretty much addicted to it (MobileMe, that is).