Well this is something that Valve haven't done before as they make ten, yes ten different games available for a free weekend.
From now until 1pm PST on Sunday (19/10/14) you will be able to get the following games for up to 80% off along with the ability to play them for free over the weekend:
- PAYDAY 2
- Company of Heroes 2
- Don't Starve
- Trine 2: Complete Story
- GRID 2
- Killing Floor
- Blade Symphony
- XCOM: Enemy Unknown
- Injustice: Gods Among Us Ultimate Edition
You can find a more definitive list of things and stuff to do with the free weekend weekend on the special store page!
Some personal picks from this list that you should check out are GRID 2, XCOM Enemy Unknown and Don't Starve.