Funny, I considered myself outlier because I didn't contact any of the professors at UPenn, mainly because the professor I admired the most had been on a sabbatical.
As for myself, I worked for a good nine years before coming to grad school - yeah, I'm pretty old. Attended a non-US university and also had lowish GPA. However, I think I had great recommendations from professors I worked with, and tried to emphasize that, although I've worked for the last 9 years, I'm passionate about research.
Best of luck to everyone!