iCal problem since upgrade
Help!
Since upgrading to Mountain Lion iCal isn't working properly on my MBA.
I've got multiple calendars, shared with my wife on iCloud. I can view all of them OK but there's a couple I can't add a new event for anymore. When I go to select the calendar I want when creating a new event they aren't there to select. They're ticked on the sidebar. They're all there to select online at iCloud.com and on my other devices but not on the MBA....
Anyone?
MacBook Air, OS X Mountain Lion (10.8.2)