When you buy a DVD, you do NOT "own" it in the usual sense of the word. You buy with the DVD the right to view/show it to yourself and a few NON-PAYING friends. It remains an intelluctual property of those who produced/copyrighted it. If you charge admission or show it to a large public group, you violate the copyright laws under which it was produced and sold. 'Sold' in this case means with an implied 'limited license' limited to the viewings mentioned above. You do NOT, for example, get any license to alter or expand the title in any way without explicit written permission of the copyright owner -- something that is almost never given. Those titles that are in 'archival' source catalogs and are listed as In The PUBLIC DOMAIN, are out of copyright, and can be shown as you please, BUT all sources from which you could rent the film/dvd will absolutely make you sign a contract that makes it clear that THEY limit you to showing it only under their terms, which MAY allow commercial showings IF you abide by their terms and pay their fees -- and return any rented prints to them. Soooo, you can't just go to the store and buy some title and put it in a machine and project it onto a screen without getting into some very hot water should the copyright owner find out. To learn more about the copyright law and the procedure to learn who owns a title or if a title is really in the public domain, go to the Copyright Clearance Office of the Library of Congress at:
www.loc.gov .
As to projecting DVDs, some posts here mention the availability of commercial machines to do just that, but John Pytlak and other experts here make it clear that so far the available resolution (detail of the image) is not equal to 35mm film, and one would have to have a small screen to make good use of the medium.
I must agree with the others, it is a VERY risky business, sad to say, of building/starting a cinema even using current films, much less so-called classics. Best Wishes in any case, from a Movie Palaces buff who very much wished that we could bring back the REAL movie going experience. Jim