Your job, should you choose to accept it, is to comment on this thread explaining the most awesome thing you've done this month. You may be as blatantly proud of yourself as you feel. You may unabashedly consider yourself the coolest freaking person ever because of that awesome thing you're dying to tell everyone about. This is the place to do just that.
Remember, however, that this isn't any kind of progress thread. Nor is it any kind of proposal thread. This thread is solely for people to talk about the awesome things they have done. Not "will do". Not "are working on". Have already done. This is to cultivate an environment of object level productivity rather than meta-productivity methods.
So, what's the coolest thing you've done this month?
Hey, terrific! Did you enjoy the book itself? I really liked AoPS series; I remember getting a whole lot out of Introduction to Counting and Probability. I distinctly remember thinking over and over, why didn't they tell me this in school!
I'm not sure what your ultimate goals are, and you're probably already familiar with the online AMC8/10/12 and Olympiad problem banks that others have mentioned; if not, I couldn't recommend them more highly for bringing newly learned skills to bear on novel problems. At one point, I worked through all the AMC8, then all of the AMC10. It became very addictive!
Also, perhaps more recreationally, the MAA does a question of the day called Minute Math, which is always good for a quick diversion.