This is a neat little online quiz that tests your ability to differentiate subtle differences between gradations in color. If you're a designer this should especially interest you.
Try it out (made by X-Rite)
Being a great fan of comic books, I always loved the visual identities used for some famous characters. Most super-heroes logos are like a incorporation of many aspects of the characters and their superpowers. I always liked Hulk logo as everytime I look at it I always remember his famous quote "Hulk Smash".