An art form developed through the use of ASCII characters. ASCII art runs the gamut from simple little doodads in someone's sig file to complicated random-dot 3-D stereogram images that are quite impressive (check out the links below!).
Here are a few ASCII art examples!
Here's a Jeep (0|||0) -- imagine you're looking at the grill plate on the front of the vehicle head-on
For all you race car fans, here's a simple ASCII art image of a dragster "O*;;;-----o~