With your Ipad plugged in, go to the information tab. Click calendar, and select the calendar you want to sync.... then sync.
It is not an iPad "problem" for sure, it just receives what iTunes sends. It is more than likely your setting up of the sync... I am not a mobile me user, so I don't know that part.... could be a setting there as well...
You do not say what calendar... in other words iCal, Outlook, Google.......etc...