Clearly, I have too much free time on my hands to go back to year 1, and forward to year 2100 on the Calendar app, but I thought I'd share these odd bugs. Items from the birthday calendar (meaning you'd have to save peoples' birthdays in their contact info) show up as two-day events. Also, if you go back in time the year numbers will go in this order, from most recent to earlier: year 5, 4, 3, 2, 1, 1, 2, 3, 4, 5. It does not show B.C. If you try to create an event in the B.C. years, nothing shows up.