Other ideas for six senses

http://www.inquiringmind.com/Archives.html

http://faculty.washington.edu/chudler/neurok.html

Optical illusions lots of information on the web - some links below:-

http://www.ritsumei.ac.jp/~akitaoka/index-e.html

http://www.colorcube.com/illusions/illusion.htm

http://www.questacon.edu.au/html/incredible_illusions.html

http://www.grand-illusions.com/

http://www.torinfo.com/illusion/directory.html

The Color of Your Food Influences How Much You Eat

origami - mathematical units http://www.merrimack.edu/~thull/phzig/phzig.html