The 2004 MacArthur Fellows have been announced. Information here. As Brian Leiter has noted, these awards are often but misleadingly described as "genius grants." It would seem more accurate to say that the awards are given to interesting people doing interesting work that the fellowship committee finds commendable and wants to recognize with an award. Of possible interest: as best I can tell from the names and pictures, there are only five white men among the 23 Fellows this year. Also, eight of the Fellowships were awarded to professors in the fields of science and engineering, and six of the eight are women.
UPDATE: A reader points to this article from Slate a few years back that provides some additional (humorous) perspective. An excerpt:
[T]he perfect MacArthur genius is still out there: a one-named Berkeley professor who choreographs interpretative jazz dances about how genetically modified food will destroy humanity.