Not only was I informed recently of the sci-fi subgenre Steampunk... Read more about it in this wikipedia article....
But I have also learned just this morning about another sci-fi subgenre: Space Opera.
Okay, I really did think it was a musical that takes place in space. That is much cooler than what Space Opera actually is: a subgenre of speculative fiction that emphasizes romantic, often melodramatic adventure, set mainly or entirely in outer space, generally involving conflict between opponents possessing advanced technologies and abilities. Blah, blah, blah...
Oh, and I also think it's very cool that Steampunk is not just a sci-fi subgenre but a clothing style that is something akin to Ren Fair meets Fetish meets Metropolis/City of Lost Children. http://www.clockworkcouture.com/
God, I'm old.