Originally Posted by Tinks
Can you please explain how this is done? Thanks. I didn't think is was possible on the nook.
This is how it works for the Sony. It will probably be the same for the nook as long as you leave the WiFi off.
Use Adobe Digital Editions to drag and drop the library book onto your reader, or add it with calibre or whatever you want. It will expire at a certain date and time. Once the book is on your device, manually change the date under the settings menu. Sonys automatically sync the date and time when you connect them to a computer (at least the 300/600/900 Readers) so as long as you don't connect it, it will continue to keep the wrong date. You can set it back a month or two on the Sony and the book on your device will never expire, even though it returns to the library you got it from and you can't open the file on your computer any more.
You could also strip the DRM and copy the book but I have no idea how to do that.
Hope this helps.