1. Create a series of coded messages for the children to decipher. You can use simple ciphers like letter substitution, and number codes, or even create your own symbols for them to decode.
2. Provide each child with a pen and paper to write down the coded messages and their decoded versions.
3. Explain the concept of ciphers and the art of code-breaking. Encourage them to think logically and use clues from the coded messages to unravel the hidden meaning. eg.
Number Code:
Code: "20 5 19 9 18 5 19"
Decode: "T E S I R E S"
Symbol Code:
Code: "@#$%^&*!"
Decode: "CODEFUN"
Word Scramble:
Code: "hrtesefa"
Decode: "feathers"
4. Place the children in pairs or small groups and distribute the coded messages to each team.
5. Allow the children time to work together, discussing the clues and attempting to crack the codes.
6. As they successfully decode messages, have them move on to more challenging ciphers to keep them engaged.
7. After the activity, gather the children to discuss their approaches and strategies for solving the codes, promoting linguistic intelligence through communication and logical-mathematical intelligence through problem-solving.
8. This activity not only stimulates logical-mathematical intelligence as children analyze patterns and apply reasoning skills, but it also enhances linguistic intelligence as they read, interpret, and communicate using language. Additionally, teamwork and collaboration among the children further develop their interpersonal intelligence.

Remember to create codes that are age-appropriate and gradually increase the complexity based on the children's abilities. The joy of cracking codes and revealing hidden messages will make this activity both entertaining and educational for the participants.