Some hardware refuses to die. More than 4 years after Barnes & Noble introduced the Nook Tablet and 2.5 years after it closed its Nook manufacturing business, the tablet is still alive and kicking. At least in the hands of the CyanogenMod maintainers.
The team, which has recently revived similarly forgotten hardware such as the Galaxy S III, Nexus 4, and Nexus 10, is back at it with the Nook Tablet. The first CM 13 nightly, based on Android 6.0 Marshmallow, is already available for download. Like other CM13 ROMs, it weighs about 250MB and you'll need to grab a corresponding GApps package to get all of your Google services and apps running.
I'm not sure how well Marshmallow runs on a 1GHz dual-core processor with 1GB of RAM, but if you still have a Nook Tablet lying in the back of some drawer and you wouldn't mind the possible bugs and instabilities, you can give it a try. Who knows, you might find a new appreciation for your old tablet.