Nothing. I kept my sanity during boards (and actually managed to up my climbing strength / endurance quite a bit, ha) and beat my goal score by two points.
A 280 is a stupidly high score, but what's the point, really? The difference between a 260 and a 280 (and even probably between a 240 and 260) is pretty minor when it comes to actually getting a residency -- all of those scores will get your application read and probably get you an interview if your grades are in line. People obsess (especially here on SDN, where the average score seems to be around 250) about getting the highest score possible. Beyond a certain point, your score really quits being that important. Once you've done really really well, that's good enough to get you the interview -- matching and actually getting the residency spot comes down to other factors.
That said, to the people that do rock 280s -- kudos. You're way smarter than me, ha.