Oddly enough, there's an Aldi on Queenschapel near the NE DC and PG County line...Hyattsville area perhaps? Dunno, just drive by it on the way to the College Park Ikea every now and then. Not everyone will feel comfortable getting out of their car in that area, but it's an Aldi and it's pretty close in.
I've shopped at Aldi in Germany and Belgium, but not here (yet). A friend who lives in rural Ireland has been gushing over the new Aldi by her village, so I guess they are pretty much everywhere by now.