Video Description: Andrei Okounkov (Russia),Grigori Perelman (Russia),Terence Tao (Australia),and Wendelin Werner (France) were awarded the Fields Medal for their contributions to mathematics. But Perelman, who proved the ''Poincaré conjecture'', refused his medal. Source:
anuglyboy.
Fields Medal. The Fields Medal is a prize awarded to two, three, or four mathematicians not over 40 years of age at each International Congress of the International Mathematical Union, a meeting that takes place every four years. The Fields Medal is often viewed as the top honor a mathematician can receive. Founded at the behest of Canadian mathematician John Charles Fields, the medal was first awarded in 1936, to Finnish mathematician Lars Ahlfors
and American mathematician Jesse Douglas, and has been regularly awarded
since 1950. Its purpose is to give recognition and support to younger
mathematical researchers who have made major contributions.
Field Medalists 2006

Andrei Okounkov, Russia, "for his contributions bridging probability, representation theory and algebraic geometry"

Grigori Perelman, Russia  Medal declined, "for his contributions to geometry and his revolutionary insights into the analytical and geometric structure of the Ricci flow"

Terence Tao, Australia, "for his contributions to partial differential equations, combinatorics, harmonic analysis and additive number theory"

Wendelin Werner, France, "for his contributions to the development of stochastic Loewner evolution, the geometry of twodimensional Brownian motion, and conformal field theory"
The next prizes will be awarded during the opening ceremony of ICM 2010 in Hyderabad, India on August 19, 2010.
Source: Wikipedia,
Fields Medal,
Fields Institute,
IMU Awards and Prizes.