I can't work this one out. MacPro (1 yr), iPad2, iPhone4 - all with latest updates. Everything working normally for many months.
Today, just with Calendar
iCloud Safari web interface working fine
iPhone4 continues to up/down sync fine with iCloud
iPad can create and upsync to iCloud, but not downsync. System restart, no change. If I create an entry on the iPad and then delete it in iCloud, iCloud pushes the creation and deletion to the iPhone, but not to the iPad or the Mac.
MacPro creates iCloud Calendar entries but cannot upsync or downsync. I notice that Cmd Refresh takes for ever. System restarted twice, no change.