To Watch and Read!
PreK and K
The Turing Code movie preview (Don't need to watch the interview after)
Code Breaking and Mathematics 1min 30 seconds
National Geographic Code Breakers--45 mins (5th grade)
Using tape or yarn create a super spy maze. I would use chairs to do this and you will probably have to recreate it every day you use it. Suitable for PreK-3rd I would think.
Gumshoe Detectives 1st-3rd
Could be any age group
Pay no attention the (wo)man behind the curtain!