Currently Being ModeratedMar 13, 2013 3:19 PM (in response to Philip Cutting)
Try resetting the iPad. Hold the on/off and home buttons together for about 10 seconds till the Apple logo appears.
If that doesn't fix the issue, try restoring through iTunes on your computer.
Currently Being ModeratedMar 13, 2013 6:15 PM (in response to Philip Cutting)
Do you have any all day events on April 1st? there's a glitch with the calendar app where any all day event on April 1 makes it crash. this includes subscribed calendars, like holiday ones. (For many the glitch is Easter Monday)
Either remove those events or edit them to last a few hours instead of all day.