Just over a week ago, Good Old Games (GOG) revamped their website and dropped their name to just GOG. No Good, no Old, no Games, just GOG. Within this new sense of identity, they're giving away the original Fallout, for free, for the next 48 hours.
You don't just get the original game, either. You get a bunch of bonus content including the 124-page manual, Fallout series wallpaper, HD wallpaper, reference card, Fallout Bible (205 pages), the soundtrack, 5 Vault Boy avatars, 18 avatars and finally, 5 artworks. Not bad for the good price of, oh wait, its free. Yes, $0. Nothing, nada.
Get in now and grab it, and enjoy the game that started the Fallout series. Fallout weighs in at 506MB and will work on Windows XP, Vista and 7 (32/64-bit). You can get it here.