If you like to play old games you may want to check GOG.com site. That site gives you possibility of purchasing old games for very cheap price (5.99 or 9.99 at the moment). Not only that will give you a game but you will get to own the game within few seconds and all that without any DRM. Once you purchase game there, you do really own it.
They do not have big library currently although you can see it expanding every month but there are some gems like Fallout or Freespace serial. Even Unreal is available. For more of them, just go to site and browse around – you will be amazed how many “good old games” made it to list.