What is Steampunk?

Definitions include:

Steampunk is a sub-genre of fantasy and speculative fiction that came into prominence in the 1980s and early 1990s. The term denotes works set in an era or world where steam power is still widely used—usually the 19th century, and often Victorian era England—but with prominent elements of either science fiction or fantasy, such as fictional technological inventions like those found in the works of H. G. Wells and Jules Verne, or real technological developments like the computer occurring at an earlier date. Other examples of steampunk contain alternate history-style presentations of "the path not taken" of such technology as dirigibles, analog computers, or digital mechanical computers (such as Charles Babbage's Analytical Engine); these frequently are presented in an idealized light, or with a presumption of functionality.

Imagine a dirty Dickensian setting, think about brass and clockworks and black iron and steam engines, add some astonishing advanced versions of this kind of heavy and visible machinery (mechanical computers maybe, or steamdriven robots, or cities on railway tracks, or something). Mix in some magic — dirty and mechanical — if you like. And don’t forget the airships! Victorian retro-futurism, usually with a twist of some kind.

For me, it is the epitome of a mix of modern technology mixed with lovely old brass Victoriana, a bit of Goth and some horror\sci-fi resulting in things that are most pleasant to the eye and are functional.

I've alway been a fan, however this genre has been brought to prominence recently by programmes such as Warehouse 13 and has introduced the general public to the general concept of Steampunk.