When I looked for how to do this, all I could find was "it can't be done." Well - exclusive to Crackberry forum readers! - here is how to copy an appointment in your calendar app!
(At least with an 8900 - I haven't tried on any other devices. Please feel free to add to the thread with other devices this works on!)
Short and sweet:
To copy an appointment, you just need to send it to yourself as an SMS.
Detailed instructions:
In "Day View", select the appt; blackberry key; scroll down to "Send as MMS"; Enter the recipient details and send.
I used an e-mail address. I didn't even have to wait to recieve the e-mail, I just
* went to the sent version of it
* opened it up
* blackberry button
* View appointment
* Blackberry button
* Add to Calendar
Easy and complete. Even copied recurring appointments.