You definitely want 366 days of math. Check it out as we are about to enter a new year!
The American Mathematical Society offers us a page-a-day desk calendar, in the usual form factor, with a mathematical tidbit for each day of this leap year: “puzzles, art, Sudoku variants, jokes, recipes, history, music, conjectures, coloring pages, quotations, poetry, theorems,…” according to author Evelyn Lamb and/or commenter Ben Orlin. (I’m not quite sure whose words these are.) Anyway, you should definitely read Orlin’s entire commentary on this calendar.
I was particularly taken by Lamb’s decision to include “quite a few pages about different number systems, like the base twenty system developed by Inupiat students in Alaska.” Check it out, and then figure out both the horizontal and vertical patterns in their chart: