This happens to me INCESSANTLY. I'm looking at my calendar events one second, and POOF!, the next second all of the events I've entered into the calendar- with the exception of birthdays that are on the actual contact information for a person- are GONE. My calendar settings are set to sync all events- no timeframe- and always have been. This happened to me nonstop on my old iPhone 3GS, and I was sure it was the phone causing this issue. Now, I have my new iPhone 5 in my hands and same ol' , different equipment. I have done EVERYTHING I can think of to prevent this from happening or to restore the data- including rebooting, holding home button and on/off at same time, etc.- and NOTHING works to restore the data. And then, just as magically as the data disappeared, POOF!- the data is back randomly sometime later. That "later" may be 5 mins, a day, several days. This is an absurd and EXASPERATING glitch that APPLE NEEDS TO FIX IMMEDIATELY!!! I'm starting to hate the iPhone and Apple in general when I continuously experience HUGE glitches like this that have a profound impact on what you're trying to accomplish within a feature that you DEPEND on... yet Apple has "never heard of that problem before". You suck, Apple. Don't send your problems out into the real world, to users who just gave you $800 for another glitchy piece of equipment that never solves your software issues.