iCal erased content after sync-ing

I just synced my iCal om my PowerBook with my .mac calendar and erased everything from the computer calendar. The old events are still on my .mac calendar but my computer iCal is empty. Is there any way to at least transfer my .mac calendar back to my computer - i'd rather not enter everything manually (there is hundreds of events)? Repeat sync did not work - iCal is still empty.