I think that a lot of the evolution of language comes from experimentation and slang. Someone had to invent every single usage in the language at one point and another, and in my opinion, the more it changes, the more alive it is.

Having said that, I don't know a lot of the modern slang anymore, but that's just because I don't move in the same circles as urban and younger folk. For awhile, I was going to poetry readings that attracted a lot of slammers, and I also went to protests that featured underground hip-hop groups. But since I've moved to the suburbs and far away, I don't encounter it much anymore. Now it's "do lunch" and "power walks". :-P

Teresa