At some point people decided it was cool to decorate their bathrooms by using subway tiles which are just rectangular bricks in a staggered layout. There is nothing particularly cool about it but it does sound sort of urban chic because nothing screams authentic like a Pottery Barn 1/2 bath. For years people have made jewelry out of old subway tokens and I can't count the amount of artistic renderings I have seen of the subway map.
Well this is a suggestion for the hipsters, if you are looking for the next thing...how about subway vinyl. Your friends and neighbors would be so impressed when they walk into your no window kitchen with the particle board cabinets and the stainless steel looking dishwasher and look down and see that brown and paint splattered flooring. To make it even more authentic add some homeless urine, Chinatown toe-nails and flasher ejaculate. You'll be the envy of all of Billyburg