The best Sangria in DC is at Jose Andres' great tapas restaurant, Jaleo.
I found the recipes for the red and white sangria online a few years ago and have it tucked away in my cookbooks. The recipes work in bulk, however, so I'll add my scaled down recipe in italics after each item.
Here goes:
Jaleo Sangria
9 ltrs red wine (scaled down 2 bottles or 1.5 liters)
24 oz orange juice 4 oz
32 oz 7up 6 oz
8 oz Rose's Lime Juice 1.5 oz
24 oz sugar 4 oz
8 oz vodka 1.5 oz
8 oz brandy 1.5 oz
2 cinnamon sticks 1/3 stick or so
diced pears and granny smith apples
Mix all items together except fruit. Sangria can be stored up to two weeks in a cooler. Add fruit one hour before service.
Yield: Five Gallons Two liters or so scaled down
The white sangria is a smaller recipe and needs no scaling down. I probably drink this more than the red sangria if I go to Jaleo.
Cava Sangria
1/4 c white grape juice
2 TBS Licor 43 or Tuaca
2 TBS Brandy
1 TBS sugar
1 bottle (750 ml) Cava (Spanish sparkling white wine, like champagne)
1/2 c sliced strawberries
12 mint leaves, fresh
Ice Cubes
Mix first 4 ingredients in pitcher until sugar dissolves. Mix in Cava, berries, and mint (I actually add the mint and sugar first and muddle a bit, but that's not the recipe). Fill glasses with ice and pour sangria over the ice.