We're a smidge late in reporting this since it started on Tuesday, but the Xbox Live Countdown to 2013 Sale may be the single best sale the Xbox 360 has ever had. Each day until December 31st consists of themed daily sales, with today's Platformers sale knocking co-op standout Rayman Origins down to just ten bucks. And on top of that, more than ten XBLA and Games on Demand titles are on sale for the diration of the promotion, such as fantastic co-op titles Sonic 4 Episode II and Simpsons Arcade. Head past the break to find out which games feature cooperative multiplayer!

Microsoft's Games on Demand service is infamous for its non-competitive prices. They often cost much more than current retail prices and seldom even go on sale. That makes this week's Games on Demand sale pretty special. Most of the sale games are pretty old, but their prices have been slashed down to just five bucks in most cases. Plus, the sale includes plenty of co-op offerings. I'm talking about Ghost Recon Advanced Warfighter, Perfect Dark Zero, Tornado Outbreak, Cloudy with a Chance of Meatballs, and Kameo, all super cheap this week.

Publisher Aksys Games has just released the Cave developed SHMUP called Deathsmiles on Xbox Live.  The full game download will set you back $30 and features two player online and local co-op play.

Sometime over the holidays we missed Microsoft posting Crackdown 2 onto the Xbox Live Games on Demand.  The four player co-op title features campaign co-op throughout - its a game with did quite the in depth review of - and for the most part - enjoyed what we got out of it.  Its currently priced at $29.99 which, surprisingly, is the price it goes for at retail.  This bucks the trend of digital releases on Xbox Live that seem to be priced higher than their retail counterparts.  

My still reigning co-op favorite shooter Rainbow Six Vegas 2 has come under fire this holiday weekend due to an unexpected - and unpleasant - surprise. It turns out that Vegas 2 and other titles featured on Xbox Live's Games on Demand service may or may not be compatible with their disc-based brothers. The worst part? There's no way to tell without buying and trying...and if your gamble doesn't pay off, Microsoft still will not give you a refund nor credit.

Just in time for the release of the first of two new DLC packs, Resident Evil 5 joins the list of great co-op titles (one of which is slated for tomorrow's XBox LIVE Co-Op Night) available through XBox LIVE's Games on Demand service.  Now, I'm sure the question many of you are asking is, "Shouldn't I just wait and buy the Resident Evil 5 Gold Edition that's set to be released in three weeks' time?"  Well, if you crunch the numbers on all of it, snagging the Games on Demand version of Resident Evil 5 ($29.99) and all of the DLC as it becomes available, which in total will come to 1520 , will set you back about $48.98.  That's just a couple dollars more than the current pre-order price for the Gold Edition on Amazon of $46.99.  To put it another way, picking up the game and the "Lost in Nightmares" DLC now gets you an additional three weeks to enjoy the new Jill and Chris chapter, as well as zombie slaying with Excella and Barry Burton in Mercenaries mode, and an additional week with the "Desperate Escape" DLC, all for just $2 more.

We reported not too long ago that Halo Wars, in addition to a couple other co-op titles, went Platinum and was now available for the low, low price of $29.99.  Well now Microsoft's sweetened the co-op pot by offering Halo Wars via download through its Games on Demand service.  While the game may not have been as widely popular as its more traditional FPS brother, Halo 3: ODST, the game is one of only a few co-op titles we've reviewed that has received the full 5 out of 5 for its co-op score.  All that co-op fun without ever having to leave the comfort of your home?  Now that's a deal.

Microsoft has added the first batch of new titles to its Games on Demand service over Xbox Live.  Among them is Saint's Row 2, a two player co-op title we rather enjoyed last year.  The game costs a staggering 3000 , which translated into real world monies is $37.50.   Considering you can get the full retail game for $28 (shipping included) I'm not quite sure you want to hop on the On-Demand bandwagon just yet.