Pyrohy, no I have not been there. I went to school in Washington for two years and for the most part I went to St. Matthew's Cathedral. That cathedral is actually worth a visit, they some beautiful byzantine style mosaics.
A few other buildings that I think are worth seeing are St. Patrick's near the capitol and the old cathedral in Baltimore if it's open.
The one place I would not go back to is the National Shrine in Washington. It's my own opinion, but that building to me is desperately ugly.
Andrew