The job takes one microSD card and two files that you download from the Internet: a CWR .img file, that you use to make the microSD card bootable; and a ManualNooter .zip file, which you do not unzip; you simply copy it onto your bootable microSD.
You will google this, and instructions of different vintage will reference different version numbers for these two files. As of this writing, for a Nook Color that came in a box with a blue dot on it, you need the 220.127.116.11 (eyeballer) version of the CWR, and the 4.6.16 version of the ManualNooter. Further instructions are here and here.
I used the 1G microSD card from my decommissioned BlackBerry Pearl, an embarrassment of a smartphone if there ever was one. The card is over three years old and it's class 4, but it worked. You will google this, and you will read that it's best if the card is class 6 or better. I'm sure that's right.
I used a Mac to make this card bootable. There are instructions for this all over Google. I liked best the ones here. They came with a screenshot of the terminal.
The Mac terminal takes a bit of typing, especially if you saved the CWM .img file somewhere awkward, like /Users/you/Documents/root_the_nook. But if you locate the .img file with the finder, you can drag it and drop it right into the command line. Who knew?
My first attempt looked alright, but any Market download I tried failed. That's when I switched from CWR 18.104.22.168+ManualNooter 4.5.2 to CWR 22.214.171.124+ManualNooter 4.6.16 -- because the more you fail, the more you google. The second try fared worse than the first: Market shut down as soon as I tried to open it, and so did Gmail.
Before my third attempt I de-registered the NC and put it back in pristine factory condition using instructions I googled further and found here. If you want to do as I did, scroll down to the post by Colchiro that mentions "wipe Davlik cache". Do as it says.
Then I re-registered the Nook, and proceeded with the rooting once again. Three was the charm. Now I have an Android Froyo tablet. I have no idea what I'll do with it. I installed a doodling app; Kate might like it.
General lesson learned: forget about banks. I've seen too big to fail, and it's Google. If it shut down tomorrow, the world would end.