I recommend reading the whole Wikipedia article as it is fascinating. Some highlights:
Apparently he is working on another one of the problems that the Millennium Prize people have designated as deserving of an award. If he solves that one, that will be another embarassing moment for them if he turns it down as well.In 1994, Perelman proved the Soul conjecture. In 2003, he proved Thurston's geometrization conjecture. This consequently solved in the affirmative the Poincaré conjecture, posed in 1904, which before its solution was viewed as one of the most important and difficult open problems in topology.In August 2006, Perelman was awarded the Fields Medal for "his contributions to geometry and his revolutionary insights into the analytical and geometric structure of the Ricci flow." Perelman declined to accept the award or to appear at the congress, stating: "I'm not interested in money or fame; I don't want to be on display like an animal in a zoo." On 22 December 2006, the scientific journal Science recognized Perelman's proof of the Poincaré conjecture as the scientific "Breakthrough of the Year", the first such recognition in the area of mathematics.On 18 March 2010, it was announced that he had met the criteria to receive the first Clay Millennium Prize for resolution of the Poincaré conjecture. On 1 July 2010, he turned down the prize of one million dollars. He additionally turned down the prestigious prize of the European Mathematical Society.
I like this guy! He seems to have the crazy idea that higher mathematics really has nothing to do with either money or fame.
So who is the other Grigory? That would be Grigory Sokolov who is possibly the finest pianist alive, but who refuses to do commercial recordings (all the CDs available are from live concerts) and, when the US and the UK put in onerous new visa requirements for touring musicians, simply canceled his concerts in those countries. He seems to share Perelman's stance. The fine arts, like classical music, really have nothing to do with how many records you sell or how many concerts you give.
Here is Grigory Sokolov, showing us how it's done:
What is it with these Russians?