Hi,
The same thing happened with my MacBook: wonky time & forgot AirPort.
I called AppleCare and walked through resetting the SMC, which solved the issue.
Here is a link to resetting the SMC:
http://support.apple.com/kb/HT1411?viewlocale=en_US
And one for removing and replacing the battery (which I found a bit confusing until I looked at this article).
http://support.apple.com/kb/ht3053
When I restarted, the time was back to normal and AirPort hooked up. However, my CPU was almost 100% used by iCal Helper and then I got Alarms for all the events from that wonky date.
After closing all the Alarms, I restarted and the computer seems to be fine now.
I hope this helps others.
Ken