Eben Hill , May 02, 1998; 01:19 p.m.
I have a similar situation and I use cardboard cut to size. I either tack it up or wedge it in. You might have to glue a few boxes together if you cannot find one big enough. This works better than curtains and blinds (which I have tried) it's cheap, easy, effective (no light leaks as with the others) and no need to install any hangers or rods. Just make sure the side that can be seen from the street is not the side with all the writing on it. You don't want to cause an eyesore for the neighbors.