Geography is a most fascinating subject; we should be teaching it nearly every day. Every time we study history, we can point out on a map where that history event took place. Every time we study an animal in science, we can point out on a map where that animal lives. Every time we read a story in reading or literature class, we can point out on a map where the author was from, and/or where the story takes place.
This isn't easily done if we have to go hunting for maps. I have two rules for this.
1. Hang big maps on the walls. (Or as big of a map as you can find.)
2. Give the students maps to color. (I even have my seniors color and mark maps.)
My favorite book for this is Uncle Josh's Outline Map Book. It has great maps of EVERYTHING in the world-- literally.
I also found some great old discarded school maps at an antique store. I picked up several of these at very low prices.