If you head over to GOG and download GOG Galaxy, the new GOG Desktop client they will give you a free copy of the PC classic System Shock 2. If you are interested you will want to check this out now as it won't last for much longer.

GOG is also running their yearly Summer Sale and have some fun quests you can complete to earn free games such as Splunky, Gabriel Knight and Dreamfall Chapters.

So much free and so little time...

https://www.gog.com/galaxy
https://www.gog.com/summer_xp