Do you want to develop your spatial intelligence and learn to think visually? How about attending Visual thinking school? It’s free, there is no formal enrollment or registration, and you don’t even need to leave your desk to do it. This online curriculum, developed by Dave Gray, includes mini-course modules such as Introduction to visual thinking, Visual communication, Visual vocabulary, Visual thinking tools, Visual thinking spaces, Sketching, Sings, symbols and icons, Information design, Visual mapping:
"This site is different every time you visit: it's continuously updated via live feeds from the web to bring you the best and most delicious images and links available: visuals to inspire, examples to follow, books to read and things to do, designed to stimulate your imagination and visual thinking."
Need a break? Check out 71 Optical Illusions by Michael Bach. They are very intriguing.