My wife told me the other day that the calendar app is missing from her phone. She has the stock ICS update. She is not rooted. I cannot find calendar anywhere on the phone or looking through the all applications. Any idea how she could have deleted the system app from the phone without root access? The calendar sync option does show up in her Google account and syncs fine. I did find another app called Jorte today in the market that appears to sync with Google calendar but the app sucks.