Art-related math (with a literacy connection...)
This is a demonstration of tessellations--how to make them.
A good introduction to topology--and has a neat demonstration of deformation
Another good introduction to topology--and a funny joke about topologists
Neat resources on symmetry (once you scroll past the advertisement)

Salt clay recipe:
  • 1 cup flour
  • 3/4 cup salt
  • 1/2 cup water
  • 1/4 cup cooking oil
  • Food coloring
Tessellations and M.C. Escher. Also has ways of making complex tessellations. This is an excellent resource.
Snowflakes are radially symmetrical and here is a webpage on the science of snowflakes--how they are formed.
Kaleidoscopes take asymmetrical items and turn them into radially symmetrical images. This page allows you to choose asymmetrical elements and then you can see how the image becomes radially symmetrical.