I was looking around for sites and found http://www.brownielocks.com. She's got a great collection of yearly, monthly, weekly and daily holidays, and it's all free, unlike the other major holiday site ($40/year, I think?) A quick look at their January listings has me already tossing around ideas for a bunch of them!
Also, a quick little update on Million Dollar Words: I am making a little demo version with 7 quizzes. Each quiz has 10 questions, and I have selected a few from multiple different individual versions I was going to do (there are a few from "Video Game Edition" and a few from the general version). I have 3 done, one almost done, one needs a few questions taken out and then 2 need some work. I would put the first version done by Sunday night with any luck :)