You know OmniFocus syncs actions as 'to do' items, not events, right? So they aren't going to show up as colored boxes on the calendar. They'll be a list down the right hand side of the window.
If they're not showing up even on the 'to do' list, something is going wrong. It's hard to tell where. You may want to email
omnifocus@omnigroup.com so our Support Ninjas can get you back on the road to synciness.