Here are a few from the vectortuts+ website:
http://vector.tutsplus.com/tutorials/text-effects/create-colorful-layered-paper-type-in-illustrator/
http://vector.tutsplus.com/tutorials/tools-tips/the-hidden-power-of-the-average-command-creating-swirly-type/
http://vector.tutsplus.com/tutorials/text-effects/creating-an-environmentally-friendly-green-type-treatment/
http://vector.tutsplus.com/tutorials/tools-tips/how-to-create-a-rainy-window-vector-background/
http://vector.tutsplus.com/designing/working-with-3d-objects-and-transparencies-to-make-a-vector-cola-bottle-design/
http://vector.tutsplus.com/tutorials/illustration/create-a-can-of-beans-by-mapping-vectors-to-a-3d-object/
I didn't even know it was possible to do but apparently you can achieve photo realistic drawings in Illustrator. I found this website which showcases some amazing drawing and added just some of the drawings below.
http://basangpanaginip.blogspot.com/2006/07/worlds-most-photorealistic-vector-art.html























