A few friends recently have recommended Soul Vegetarian's Exodus, a vegan carryout at Georgia and Euclid, and it is tasty stuff.
I tried the mac and cheese (made with fresh soy cheese) and it was pretty delicious -- it really seems like real cheese. The veggie burgers are good too: my buddy recommends the Garvey burger and the vegan steak and cheese. Another friend, who isn't even a vegetarian, says he's a fan of the veggie burgers as well.
They also have some buffet style food, soul food like collared greens, and other items like tofu curry. Prices are reasonable: the Garvey burger, for example, is $5. My buddy recommended calling ahead and picking it up, as it can take awhile if you're getting it to go.
The Post had a positive review last year, and here's their Yelp page. It's run by a religious group called the African Hebrew Israelites, who I am pretty sure are not the same people who stand at the Metro and yell.
Soul Vegetarian Carryout is at 2606 Georgia Avenue NW, and their phone is 202-328-7685. They're open Monday through Saturday 11 a.m. to 9 p.m. and Sunday 11 a.m. to 3 p.m. Here's their website, though there's not much on it.