I could guessed you were gonna get a lot of people dissing you for starting a thread like this, but there's nothing wrong with thinking ahead about how you're going to match the competition.
So, here are some ideas to start you off
1. Publications: coauthorship is good, first authorship is better. If you want to know some tricks and tips that can increase your probability of getting this, let me know.
2. Volunteering in a foriegn country, esp. Latin America, Africa, and rural China. While not in any way better than volunteering right here in the states, it stands out more. On the other hand, it's quite expensive.
3. Supporting a family of three singlehandedly at the age of 15. I wouldn't recommend this experience, although it will make you stand out.
4. Starting a public service program (e.g., mentoring kids with chronic diseases, etc.).
5. One of the people I met on the interview trail was a TV producer. Way cool. Everyone knew the show, too!
6. Clearing landmines in Cambodia or Afghanistan. Better (or at least, better for the future surgeon who needs all limbs intact) -- figure out a way to clear landmines automatically!
My personal oppinion is that solid research (not a research 'experience', which basically means you didn't do anything) is the golden road, volunteering in a foriegn country is the toll road.
Any other ideas, anyone?