It's another buy-two, get the third free bonanza, this time offered by Toys R Us. But it covers their entire game catalog - consoles, handhelds, everything. As you can see, the flyer above says you can pick from 800 games.
The sale will last the entire week. It doesn't sound like it coves pre-orders, but I could be wrong. It also looks like it covers accessories, priced up to $100, and so points cards are covered by that too. But that probably means you have to buy two accessories and get a third free, not mix-and-match games and accessories. Definitely ask your local Toys R Us when planning your strategy.
f you're hanging on what third title to pick, some good advice is to just get a second copy of a brand-new game for free and use it as tradebait for store credit later or flip it on half.com. Either way, they're giving away games. Don't waste the pick.
Toys R Us Buy 2 Get 1 Free Game Sale (10/11 to 10/17) [Cheap Ass Gamer, registration required]