| I learned from Luc Sante's book Low Life: Lures and Snares of Old New York that when temperance activists tried to outlaw liquor sales on Sunday in New York toward the last part of the 19th century, the brick sandwich came to saloon-owners' rescue. As many municipalities are even now doing, the movement at that time and place was to prohibit establishments from selling alcohol if they did not derive a significant portion of their revenue from food sales. The idea must have been that well-fed drunks are less dangerous and offensive than those who take no solid nourishment (an arguable point, but weird territory to legislate, IMO).
So, the dives of the 1880s Lower East Side, the "suicide halls" and "tubs of blood," worked their way around the pointless laws that were enacted by introducing the brick sandwich. Basically, beer and liquor were sold very cheap in these joints, but you had to buy a brick sandwich with every round--this was, literally, a brick between two slices of bread. Of course, no one ate them, but the idea was that when the local authorities came to clamp down on the sham, the patrons would defend the "restaurant."
"Nobody can eat bricks," the cops said.
"Ah, but it's the bricks what makes 'em so tasty!" countered the regulars, nibbling on the bread part of their brick sandwiches.
"Best brick sandwiches in town," fellow patrons would affirm.
One of my favorite bars in my new adopted city is facing closing down on Sundays due to similar city ordinances. They tried selling real food for a while, but it didn't catch on...so I suggested to the owner that he try this simple, well-established trick. In the wretched Year of Our Lord 2002, he scratched his head and thought about it--seriously--for a while. I'll update this w-u should he attempt that extreme civil disobedience pole-vault.
Update 2006: Alas, this is never to be. The owner sold the bar, and as far as I know left town. | 
