I think YouTube Video Editor might be the biggest hidden easter egg of them all. Its too bad Google or YouTube does not promote it better. This is the first in a series of videos on some of its functionality.
Normally where I need to cut is the beginning and end of my screencasting videos. I usually have some transitioning video on either end that I need cut out. Although a little more complicated, the YouTube Video Editor can also cut clips from the middle of the video.