I have certain events in an iCloud calendar that are not showing up in the Calendar app on my MacBook Pro. They show up on www.icloud.com and they show up on the Calendar app on my iPhone. Other events in the same calendar do show up on my MacBook Pro. I can't see anything different about the events that do not show up.
MacBook Pro (15-inch, Mid 2012), OS X Mountain Lion (10.8.2)