A new program launched by GOG.com means incredible value for PC gamers.
GOG connect allows you to duplicate games from your Steam library to your GOG account by connecting the two.
Assuming you own one of the listed titles on Steam, A DRM-free version of the game will also appear in your GOG library, and is yours to keep as if you had purchased the game directly off of the GOG store.
While the duplicates are permanent, the eligible games are only available for a limited time.
Currently 23 titles are in the list of games eligible for GOG Connect. You can find a full list of the available games, as well as additional games that will be added to the service, here.