Q: Apple Calendar not updating with iCloud

First check that all your settings are correct, that calendar syncing is checked on all devices (system preferences > iCloud on a mac and settings > iCloud on a iPhone, iPad or iPod).

Make sure the calendars you are using are in your 'iCloud' account and not an 'On My Mac', 'On My Phone' or other non iCloud account (you can do this by clicking/tapping the calendar button in the top left corner of the application ), non iCloud calendars will not sync.

If you are sure that everything is set up correctly and your calendars are in the iCloud account, you might try unchecking calendar syncing in the iCloud settings, restarting your device and then re-enabling calendar syncing settings.

If none of them worked you have failed to correctly setup iCloud. Start again, ensure that your account entry is correct on all devices and that you are using iCloud's calendars not On My Mac, or On My Phone etc.

Whilst you have said it isn't, it sounds to me as though you are creating events on a non-iCloud calendar.

Have to agree with Winston, it sounds as if you are not using the iCloud calendar, these are the expected results of that scenario

Have you tried creating a new empty calendar in the iCloud account and moving a few events from the non-functioning calendar to see if they will sync.

Go take a look at www.icloud.com, what is on the calendar there?

Then sign out of iCloud on the errant machine, close SysPrefs, open SysPrefs and sign back in.

Open iCal>Preferences>Accounts and take a screenshot of the settings, post it here