I think the calendar feature is pretty nice - but, at least for me not of any use at the time.
When tickets arrive (usually they are sent by mail and piped from pop3) and are assigned automatically to different staff members. The tickets will be worked on ... or not (unfortunately) ... depending on the staff member).
I - as admin - would like to be able to set a "automatic due after X days" (where X is a value which I can define). Then, when tickets arrive, they get this due date (arrival date + X days) and if the staff member has not worked on them, they get reminded by mail.
I hope I made my point
Olaf