I often forget just how good the original Watch Dogs was (here's Christopher's review for a reminder). Yes, it basically gave you what you expected from an Ubisoft third-person action game, but it had enough fresh ideas to make it worth playing. If you didn't get the chance to create a ten-car pileup by hacking some street lights with protagonist Aiden Pearce's smart phone the first time around, now's your chance. The game will be free from tomorrow for a week via Ubisoft's digital distribution platform Uplay.
That last bit is important, because some people swear off Uplay, but to get a free game of this quality I think it's probably worth logging back in or creating an account, even if you don't end up playing another game through the service. I haven't used it in years—it's been so long that it wouldn't even send me a password recovery email when I went to check today.
So, the deal opens up 4pm GMT/11am ET tomorrow, but you can preload the game before that. Some accounts have been having issues accessing the deal, an issue that Ubisoft says has been fixed this afternoon.