I see from some of your other posts that you are considering some very selective colleges. These schools are looking for achievement and/or leadership. Signing up for more clubs is not really going to help. There is a thread with several posts by Northstarmom, a Ivy alum interviewer, about what constitutes impressive ECs from the point of view of the most selective colleges. The post is at http://talk.collegeconfidential.com/what-my-chances/210497-those-ecs-weak-so-what-s-good.html
Rather than starting something brand-new, in which it will be hard to make much impact in the year before you start filling out college apps, I suggest you look to deepen the things you do now. 2 very interesting articles about ECs that stand out and how to get them (same author, different examples) are at http://calnewport.com/blog/2008/05/28/the-art-of-activity-innovation-how-to-be-impressive-without-an-impressive-amount-of-work/ and http://calnewport.com/blog/2008/09/12/case-study-how-could-we-save-this-ridiculously-overloaded-grind/ The author, Cal Newport, is an Associate Professor at Georgetown University and the author of a few books on how to succeed in college. While I don’t agree with everything in the articles, take a look at them and I think you’ll get some original ideas.