I was not aware of this, but there is now a prize in mathematics that more closely resembles a Nobel prize. It is called the Abel Prize, (after Niels Henrik Abel) and has awarded prizes in 2003 and 2004.
As is well known, there is no Nobel Prize in Mathematics. Instead, most people have looked to the Fields Medal as the most prestigious award for mathematical achievement. The Fields Medal, however, differs significantly from the Nobel Prize in that it is only awarded every four years (at each meeting of the International Congress of Mathematicians), to two, three or four recipients. Moreover, it is only awarded to mathematicians not older than 40, in order to encourage further achievements. This also has the pleasant side effect of rewarding recent work, rather than work done half a century earlier, as is too often the case with Nobel Prizes. Tellingly, both Atiyah (1966) and Serre (1954) have also won Fields Medals.
The Abel Prize, by contrast, seems to resemble the Nobel Prize more closely. It is awarded annually by a Scandinavian learned society (the Nobel Prize is awarded by the Swedish Academy of Sciences), it is worth a considerable amount of money, and so far all three recipients are over seventy years old. Happily, this allows rewarding those (relatively few) mathematicians who missed the Fields Medals due to their age.
This year's winners: Michael Attiyah and Isadore Singer for the discovery of the index theorem (explained here by John Rognes)