Science Fairs, Olympiads ...

There are billions of things you can do before applying to MIT, many of which you probably have already done. No doubt, you have won gold medals in the IMO(Math), IPhO(Physics), IChO(Chemistry), IBO(Biology), IAO(Astronomy), IOI(Informatics), ILO(Linguistics), IPO(Prattiness) and the rest. You have won the Intel Science Fair for the last 32768 years and your projects were admired by the great Einstein himself. Chill... You don't have to do so many things to get into MIT, you know(although they are pretty awesome opportunities). Just take a few things and put your heart and soul in them. It'll work out, trust us.

The Olympiads are a bit like the Olympics for intellectual pursuits. They also include Ultimate Frisbee and Mafia tournaments as official sports. So, while you prepare to win all those gold medals, remember to learn some Mafia techniques. http://en.wikipedia.org/wiki/Mafia_(game). An occasional game of frisbee would also noy go amiss.

Art of Problem Solving/Mathlinks is a very useful resource for people interested in the Math Olympiad. Check it out!