Drag, drop, copy on iPhone and iPad
Two things:
1) You can drag a calendar event by touch and hold until the handles appear, then drag in time, or even across days in week view etc.
2) there *is* a workaround for the lack of copy and paste in calendar I just found. Take the event you want to duplicate and edit it. Now set it as a repeating event with a terminal date (repeat until the next day or whatever). Push done. Now you have multiple events. Drag the second one anywhere you want (see 1 above). You will have to tell it change this event only when it asks. Ta Daaaa! you have just accomplished a copy and paste to a new time. If you know you will have weekly events (say, PT appointments) but the time will vary, just duplicate for however many weeks you need, them move them around individually. It's clumsy, slow, and awkward, but that's Apple for you, the master of conceptual integrity (sarcasm)...
3) just found *another* way. Create a google account (if you don't already have one). Sync your calendars between Google and iPhone. (see google site for mobile Google sync instructions.) Now you can duplicate and drag and drop to your hearts content on the google calendar. Changes will sync back to iPhone. You can even go to google on safari for those times you need to duplicate and drag items, and they will appear in your iGadget calendar.