You can move a video clip from one Event to another, which can help keep your clips organized in ways that make sense to you.
To move video clips from one Event to another:
In the Event Library, click to select the Event with the video you want to move.
In the Event browser, select the clip or clips you want to move.
Drag the clips to the name of the other Event in the Event Library to which you want to move them.
Release the mouse button when you see the name of the Event highlighted.
The Event you moved the clips to may change placement in the Event Library. It will be listed below the year in which its most recent clip was recorded.
If you drag a large clip from an Event stored on one hard disk to an Event stored on another, the move may take a few minutes.
You can copy, but not move, a clip from iPhoto Videos to another Event.