Originally Posted by HunterBoss
For my actions with specific start and stop times, I want them to show up as appointments.
Is that possible?
As pvonk said, that's not in keeping with the GTD philosophy. In OmniFocus, actions don't have start and stop times. They have start dates--dates at which it becomes possible or reasonable to think about doing them--and due dates, i.e. dates when they absolutely must be done. (And believe me, you'll get much more mileage out of GTD if you only enter due dates when they're really absolute.) That's not the same as an appointment, unless your appointments routinely extend over several days and can overlap with dozens of other appointments.
If you haven't read David Allen's Getting Things Done
, I highly recommend it. If you decide that Allen's approach won't help you, then OmniFocus is probably not the task management application that you need.