Besides swapping out the plastic shopping bags for reusable bags in the bookstore as Maya suggested from the NYU sustainability plan, I think it would also be fairly easy to have the computer lab change the settings of the printers so that everything that is printed comes out double sided. And although it was very irritating in the summer to walk into a dimly lit Marshak, its actually worth it since there's not that many people that congregate on the street level, so dimming the lights there should become something that is regularly done during that time of the year.