I know for a fact, the next time I’m in New York, I’m going to the Brooklyn Superhero Supply Co. They sell all sorts of awesome (read: fake) superhero related things like invisibility dust, and capes, and all sorts of great things for your inner child (read: nerd). It’s really too bad they don’t have more pictures of the things they sell and their signage.
BUT! I did find this great Flickr set with a lot of images of the crazy things they sell. Definitely give it a look!