All--
Just a little bit of advice...
It's really important to tie 2+2 into your future goals (e.g. why 2+2 would allow you to do something you previously didn't consider--even if it's as simple as attending biz school instead of law school, med school, etc.--or how HBS in general could give you a distinct experience from any other traditional business school or graduate school). If you come off (even unintentionally) as someone who would apply to HBS anyway, the program's probably not for you.
While stats and organizational involvement are VERY important just to be considered (and certainly to be eventually admitted), you are wasting your time if you can't skillfully articulate how you will both get something unique out of 2+2 and contribute some sort of diverse background to the program. If you can articulate how HBS in general will set you along an even better life path post-MBA, that's even better. (My thoughts: even if you aren't 100% sure of what you want to do with your life, it's better to posit a few specific suggestions, maybe even linking in specific classes/profs/organizations at HBS that will allow you to accomplish these goals.)
I hope that my message isn't too cryptic...it's certainly not supposed to be. Looking back on the admissions process last year, I realize the that we applicants probably disproportionately emphasized stats, internships, etc. The truth is that there will (likely) be a few students with GMATs in the mid-600s accepted and probably at least a student or two with a 790 or 800 rejected. GMAT (or I guess GRE this year) and grades just get you in the door and don't necessarily shut you out if you can convince HBS otherwise, especially for this program.
