The original Watch Dogs is available for free for a limited time for those registered for Ubisoft’s Uplay service...the promotion runs from Nov. 7 through Nov. 13 and only applies to the PC version of the game...the game is yours permanently as long as you download it within the specified time period...
https://freetrial.ubisoft.com/promotions/watch-dogs-1/8/
https://freetrial.ubisoft.com/promotions/watch-dogs-1/8/