We use a bunch of free ones around the house, but there are three I've bought regularly for years, all of which have come in this week.

Over my desk I have a large Runner's World calendar.
For logging my runs, I use
And for carrying around in the case with my dance laptop, a 3-year callers calendar (with major conventions and festivals listed), from Palomino Records
Do you have any favorites? Or regulars? Gone hi-tech?