This is a fantastic critical thinking website that also taps into math, linguistics, engineering, and analyzing skills.

Blog post about using it:

Use various tools (code, morse code, QR, etc.) and evaluate how well each one worked.

Contest (like catapults) with judgements in various categories.

Expand to go to visual messages.

Decipher the Postal Bar Code

Break the Code

In this logic game, a player uses clues to help them break a hidden code in as few guesses as possible. 

Binary Dots

Counting in binary is quite straightforward and makes for an interesting and compelling activity for any student who can do simple addition. This uncomplicated game creates an opportunity to practice counting in binary. It reinforces understanding of place value and can be extended into a discussion of other bases and number systems. 

Binary Weaving

Computers use binary numbers (Base 2), a series on "ons" and "offs" that encode information. In this activity, students use the Ascii alphabet to encode a message into woven band, and then other students can decode the information. 

Floppy Spirit Drum

Create these wonderful spirit drums to celebrate Chinese New Year and then use all year long.

Prism Heddle Loom

This simple loom encodes patterns into a prism-shaped piece of cardstock.