Woot! Just like the name implies, the gray area of computer gaming... downloading games of the last several decades that are still technically protected by copyright but are commercially unavailable, allowing companies to let their games slip into oblivion by ceasing production and sale, then prosecuting anyone who releases the games to play.
US copyright law has recently changed to make software that is otherwise unavailable for purchase legal to download and play.
Science Fiction Observer: USA Legalizes Abandonware