Websites

• Codes and Code Breaking
• Computer Science Unplugged
• Cryptology Club
• Fibonnacci Math for Kids
• Fractal Foundation
• Numbers in Nature
• Make Your Own Geometric Drawing
• Vi Hart (a self-described "recreational mathemusician")

Books

By Nature's Design: An Exploratorium Book
Diane Ackerman

The Golden Section: Nature's Greatest Secret
Scott Olson

Growing Patterns: Fibonacci Numbers in Nature
Sarah C. Campbell

Mathematics: The Science of Patterns

The Search for Order in Life, Mind and the Universe
Keith Devlin

Symmetry: The Ordering Principle
David Wade