This looks cool - enter a term into this search engine and not only does it find a picture, it converts on the fly to ascii art, such as these: [Accessibility warning - you don't want to follow these links in a screen reader unless you like hearing meaningless repetitive text for a long time.]
It works better with images with lots of contrast and big details - for others sometimes you have to go to Google Image Search to figure out what the picture was before transformation (such as this picture found for "Darth Vader" - the text version is hard to figure out until you see the gorgeous original picture).