What is a good, cly place to celebrate my 21st birthday in DC?

I'm going to be living in Washington DC this summer and working. I'm also turning 21, and with a few friends in town and some visiting that weekend, I am looking for a good, upscale place to celebrate. I've never been one for wall to wall packed loud venues with a lot of drunks all over. I'd rather someplace near or within a reasonable distance from Foggy Bottom that we can wear suits or something similar and enjoy a nice evening. I had looked at POV which seemed to have the perfect atmosphere but the ratings on service were terrible. Help?