TubeChop

TubeChop is a great YouTube editing tool.  No need to register or log in.

As a teacher, I often just want to show a piece, or a series of pieces of a video to a class.  TubeChop makes this easy.  Just grab the URL for the YouTube video you want to edit (or do a keyword search from the YouChop site) and paste it into the text box on the YouChop homepage.  YouChop with then load it into the editor and you can choose a range of time (the portion of the video you want to watch) using a slider for start and finish.  Then "Chop It".

The site will them give you a link and embed code that you can use to disseminate the finished product.  Very easy and very convenient.

Give it a try.  Here is the resulting 10 second piece that I cut from a 5 minute video