GamersGate is joining the wave of seasonal discounts with their Summer Sale program, cutting the prices on over 5,000 games with savings between 40% to 75% off. There's daily deals, weeklong deals, and various publisher specific bundles all on offer.
As of this writing, I see DmC going for $24.98 and Metro: Last Light for $33.47. Other massive deals includes the Telltale Games bundle consisting of all the Sam & Max, Puzzle Agent, Back to the Future, and Hector: Badge of Carnage games for $37.50.
You have until August 5 to snatch up any of these discounted games on the PC or Mac.