For some reason I've got some rogue items in my calender on my iPhone 4 (iOS 4.2.1). They appear on my iPhone, but not on my MobileMe web calendar OR my iCal on my Macbook Pro (which is also synced). I already tried removing the calendar from the iPhone: Settings > Mail, Contacts, Calendar > MobileMe account There i deselected the calendar followed my "Remove from iPhone". All items where removed, calendar was empty. I reselected the calendar ans let it sync. Everything returned again, also the many duplicates. I also tried removing them manually from my iPhone, but after deleting them, they dissapear for a ms and then return.