Origin's 'On The House' deal is simple: EA makes on of its games free for a certain length of time. Pretty cool. Plenty of cool games have been chosen in the past: Battlefield 3, Dead Space, Peggle. Right now, as of today, Syndicate is the latest game 'On The House'.
I'm talking about the original Syndicate, not the weird FPS reboot that made no sense whatsoever.
Syndicate is a proper cult classic. A proper one. I suggest checking it out for cool cool price of 'free'.