ES = Elementary School
MS = Middle School
HS = High School
Using a calendar to cultivate a looking forward habit is a great game to play with your kids, especially in the early years. It introduces them to the concept of time. I think the key is to have a healthy dose of fun stuff to talk about to get them excited about coming to this magical tool we call a calendar.
"Hey, look here. I see your birthday is one month away!"
"Wow, only 1 week until your birthday!"
"Your friend is coming over for a play date in 2 days."
"I see the school dance is next Friday."
"If you could plan a cool trip this summer (3 months away), what would it be?"
If you start in the early years, when you get the the later years you won't have to introduce "here is a calendar and here is how you use it." It will be natural - hopefully mystical and magical, too.