Rounding fractional numbers to nearest fraction

Hi all,

I've got a matrix of fractional data that is all positive and greater than 
zero that I would like to "loosely" classify, for lack of a better word. It 
looks something like this :

1.07   1.11   1.27   1.59   0.97   0.76
2.23   0.98   0.71   0.88   1.19   1.02


What I'm looking for is a way to round these numbers to the nearest 0.25, 
i.e. the above matrix would be transformed to :

1.00   1.00   1.25   1.50   1.00   0.75
2.25   1.00   0.75   1.00   1.25   1.00


Anyone have a clever way to do this??

Thanks in advance,
Ken