If you cannot see the calendar on your iPhone please follow these instructions.
Enabling cookies using Safari for iOS (iPhone/iPad/iPod touch)
From your Home screen, go to Settings > Safari.
For iOS 7: set Block Cookies to Never. For iOS 6 and below: set Accept Cookies to Always. Once this is set, you can browse OverDrive-powered websites normally.
If this did not work please try using a different browser or device to view this calendar.