Dr. Who aired in Britain. A few years ago someone got the bright idea to commemorate that anniversary by declaring November 23 Dr. Who Day.
Our favorite Doctor was Tom Baker, the Fourth Doctor, perhaps because his adventures were the first to be shown in Chicago. Although the special effects left almost everything to be desired, the show has taken on a life of its own and a multi-generational following. What are they on, now? The 27th Doctor? Wasn't there some Gallifreyan limit on the number of times a Time Lord could regenerate? These are questions you may take up today.
Buy Nothing Day was -- not surprisingly -- instituted in revulsion to Black Friday. (Oh, yeah, we suppose today is also, technically, Black Friday. But, if you're driving around the mall parking lot in an increasingly desperate search for a semi-legal parking space you probably aren't reading this post. At least we hope you're not reading this post while you're driving!)
Flossing Day also has a Thanksgiving Day tie-in: Dental professionals urge you to floss today after the excess binging of yesterday.
Usual Suspect brownielocks.com mentions that today is also Sink Day -- also related to Thanksgiving in that, today, you may be inclined to eat leftovers hunched over the kitchen sink, every dish you own being stacked, unwashed, beneath.
You probably wished you had a TARDIS when all the relatives showed up for dinner yesterday, didn't you?