So I got my first flash, a 600EX-RT. So far I just got a Gary Fong Lighsphere diffuser for it and that's about it. I was just curious as to what fun things I can do with it just to experiment. I've always shot with natural light/reflectors, but I know flashes open up a whole new world. I feel like I'm clueless as to where to start, so any advice would be greatly appreciated!
I would even suggest getting Joe McNally's book Sketching Light. I have that and Syl' book and they are great, and the most reccomended books on the strobist.com