I don't know your interests and inclinations, but I would say aim for something fun and/or creative, but not expensive - something that requires mainly an investment of time.
Here are some examples from my own life. I love music of most kinds, but especially the blues. I have been playing for years, and that still helps me. I also like poetry; sometimes I will just get a cool-looking anthology for a few bucks and curl up with it over a cup of tea. And sometimes I write poetry.
I am also a teacher and writer by profession, as you know, and I guess I am pretty academic and nerdy about many things. So I have started a book on CSA in world cinema. I got a grant to buy DVDs, but if that had fallen through I could have just rented them for cheap from Blockbuster, one at a time.
If I were going to be alone over a major holiday I think I would want to create a tradition for myself - something I could do year after year. How about taking Little Steve to a big toy store to look around, and then a cool meal somewhere - wouldn't have to be expensive. Or going on a hike or walk at some nearby place of natural beauty. Or go to an art of museum exhibition somewhere.
I think it's worthwhile for all of us, even if we're in a happy healthy relationship or have a busy family life, to do fun creative things stressing that we can also be interesting company for ourselves and that being alone doesn't have to cut us off from enjoyment of our time.
Nobody living can ever stop me
As I go walking my freedom highway.
Nobody living can make me turn back:
This land was made for you and me. (Woody Guthrie)