Group By

[chester]

I have a table with two columns.

| username         |  score          |

I wish to select the top five scores for distinct users using only 
one query. When I do a GROUP BY command it selects their first score, 
I want it to sort the scores, and then select distinct users so that 
I get a list of five unique users and their highest score.

Any way to do that using one query?