Solving Poincare Conjecture problem

Recently International Mathematical Union (IMU), announched 2006 Fields Medal (equivalent of Nobel Prize in mathematics) winner. One of the winners is Grigori Perelman who has solved the Poincare Conjecture Problem that is regarded one of the most difficult problems in mathematics since hundred years when it was found. The Poincare conjecture essentially says that in three dimensions you cannot transform a doughnut shape into a sphere without ripping it, although any shape without a hole can be stretched or shrunk into a sphere.

However the acclaimed mathematician refused to accept this award and another award of $1 million for solving this problem.
This makes me wonder that there are people in this world who are not fazed by the fame and money involved in pursuing a pure academic career. But for the pure joy of solving such mysteries that has kept the human mind always puzzled and thinking.