GameFly / GameFly UK has a WB Weekend Sale going on. Various Warner Brothers games are on sale. There’s no explicity $5 Fridays sale going on but it looks like a number of games are $4.99 so maybe they just merge the two sales this week?
Batman: Arkham City Game of the Year Edition = $23.99
F.E.A.R. 3 = $4.99 – Steamworks