I created Math Spies as a set of paper pencil activities to use in a math enrichment class I taught about ten years ago. Last year I started posting missions for my class at Math Spies.(mathspies.blogspot.com)
Math Spies Episode 3is a web based activity. Students solve four number puzzles for each mission. This gives them a set of coordinates to enter into Google Maps. They take each code word associated with the closest location and assemble it to make the secret message.
Attached is the worksheet I use to help students keep track of their answers and the key.