Basically whatever you write with the pen (on a special paper) is recorded. Both your voice and what is recorded so you have video and audio. When you play back it is all there for you to watch and listen. I used the smart pen to record various demonstrations for students to watch at home for either a review or if the student were absent. I also recorded solutions to study guide problems in preparation for a test or quiz.
The videos are quickly uploaded to the Livescribe site. I embedded the videos on my classroom website to make access easier. This usually took me about 5-10 minutes to complete after the video was finished.
Of course there are lots of other uses for the smart pens. You can check them out at http://www.livescribe.com/en-us/.