The following education related Nook downloads are good until 1/17/2011.
Kaplan AP Biology
From Here to Freshman Year
Caffeine Will Not Help You Pass That Test
Legally Speaking, Revised and Updated
There are a lot of other free Nook downloads for free available here.
These can be read on the Nook reader or you can download the app for PC, iPad, Android, iPhone, etc. I use the PC app, and I have been downloading whatever free books look interesting, in case I get a Nook reader...