It is true that you can't do too many things well. I was just trying to give several examples of how you could get ECs. From what I have observed through this process there seems to be emphasis in the areas of leadership, self motivation, physical fitness, grades, test scores, awards received, military interest, consistency, and the ability to articulate why you want a scholarship, appointment etc. There are many ways you can show these qualities through one EC.
For example a member of JROTC or CAP could start a PT team (if there isn't one) during his sophomore year. If he commanded the team through his senior year it would show interest in the military, physical fitness, leadership, initiative and consistency.
If you earn a good grade point you will be selected for National Honor Society. You need to volunteer for this club. If you volunteer teaching computers (as discussed in my original post) you get the necessary hours for NHS and you have community service on you CV. This shows you are a well rounded (whole person).
Like the last poster states don't do so many things that it looks like you just did them to check a box. The ECs you do choose should be done with the qualities the military is looking for in a scholar athlete. If you can check off more that one box (athlete vs. athlete, team captain, record holder/league champion, starting new team) you are getting more out of your EC and you can concentrate on doing well on the few you are doing. Again, good luck!
It would be nice if others could give examples of some, "Out of the box" ECs they have done that worked well and helped them with their goals.