I see tonight that Adam Riess of the Space Telescope Science Institute in Maryland won a MacArthur Genius grant for $500,000. Which is great for him. But it must have been a tricky decision. Saul Perlmutter ('s group) and Adam Riess ('s group) went head-to-head in discovering the acceleration of the expansion of the universe, and to date both have received nearly equal recognition of it (for example, they shared the 2007 Gruber Prize), and I think it's generally acknowledged that, if a Nobel Prize is given to this discovery (and it most probably will be), both would share it. This is one of the first asymmetries in their recognition.
PS: I wrote a profile of Saul Perlmutter that appeared in this April's Scientific American, and Robert Kischner (from Harvard, of Reiss's group) and I had an exchange of comments in the August issue of SciAm. I looked into this issue of priority a good bit, and thought that Kutner's own interpretation of "Getting it First" (Perlmutter) versus "Getting it Right" (Riess) was pretty much right, if perhaps a bit slanted towards Riess and away from Perlmutter. Though I didn't interview Riess and I admit it's a very tricky, touchy subject. Lots of fodder for future science historians.