Think of sports and arts.
NCAA D-1 athlete (team or individual sport)
Nationally ranked athlete (Olympic trials, that kind of stuff)
Pianist who's won numerous regional, national or even international competitions
Filmmaker who got his/her indie feature into the festival circuit
Political/social activist who has won recognition in the form of notable press, awards, and commendations
In other words, having some sort of extraordinary talent and getting recognized for it - but obviously not enough to make it full-time consistently (otherwise they wouldn't be applying to b-school). In other words, we're not talking Michael Phelps, but the guy who was good enough to make it to the US Championships but couldn't quite make the cut on the men's Olympic squad, or the filmmaker who managed to get his film into film festivals, but wasn't able to turn that into a full fledged career. Or the guy who played on the PGA tour for a bit.
Of course not everyone has this, but most people at HBS and Stanford have pedigree - they went to top schools and work at employers that are hard to get jobs at (Goldman, Google, etc.). If you don't have this, then you should have something like this. And while there are folks who have neither at both schools, they are in the minority at these schools - and they were lucky.
Alex Chu
alex@mbaapply.com
www.mbaapply.com
http://mbaapply.blogspot.com