Why are my iCal events (future events) just dissapearing?

Not using iCloud or mobile me. I am syncing my iPhone via iTunes.

Yesterday afternoon I created several new iCal events for today's and next week's calendar. This morning when I opened my iCal none of my new events were present. This morning, I recreated some of tomorrow's events. Closed/re-opend iCal to find the events had disappeared again. Also, seeminly unconnected but equally buggy - event alarms can be 1,2 3 hours late - radomly. ughhh!