Here is a calendar I highly recommend: the It's Different Every Day calendar, which is currently on Kickstarter for its 2016 version. I have the 2015 one this year and it is great: fun and interesting facts, little stories, drawing, games and puzzles, etc. I love that every time you tear off the page you never know what's coming up next. My kids (age 8 and 10) love it too.
Check out their Kickstarter page here to order yours for 2016! It's fun, interesting, and Different Every Day!