I work for a big organization that puts on a lot of events like training workshops and conferences. A lot of these events recur irregularly a few times each year. The managers of these events love that they can now input their events without asking me to do it for them. What they all say would be even better is if they could duplicate one event they've already created and then edit the details that change like date/time, registration link, location, etc. Right now they have to start from scratch creating a brand new entry over and over and over when 80% of the event details are identical to the other entries they've already put into the system.
So how about a button on the CP for Entries that makes admin options something like this:
with a popup prompt to select a recently-added entry to duplicate.