Ahhh, January. The clean slate of a fresh new year...and a fresh blank calendar. Oh, the promise and mystery it holds. While I use iCal on my computer and iPhone for business, I always like to have an "analog" version on the walls in my office since they serve as great artwork and often, interesting design perspectives on tracking the passage of time.
A perennial favorite of mine (and I'm pretty sure graphic designers across the globe) is Pentagram's 365 large-format calendar. Pass the time with a new typeface (and a short story on its origins) each month: available from Veer.
This series also includes a moon phase version. Punch-out the circles every day or just important dates, creating different abtract designs in the process from designer Michael Domberger. All available at Amazon.
Along the "interactive" calendar idea, I love the concept behind the Apple-a-Day calendar by Vik Design. Count down the days to better health with the sticker from the apple you ate that day. (Can we sneak in the banana ones, too?) Aavailable on Vik Design's Etsy shop.
When it comes to illustrative print calendars, my new favorite is from Papersource. What is so great about these is they not only use PS's great recycled paper designs, but there are templates on the back of each month to make things (cards, favor boxes, etc.) when you are through with the calendar. Available at Papersource.