Along with the BioWare reveal, VGA emcee Geoff Keighley also tweeted that the event would feature a new trailer for Batman: Arkham City. The show should also reveal the Guillermo Del Toro project over at THQ and maybe, just maybe, something involving Gears of War and Kinect.
Update: The sharp eyes of commenter Arth Vader picked up that the gun in the pic is either the M-29 Incisor Sniper Rifle from the Mass Effect 2 Aegis Pack DLC or a reused asset. If it is the M-29, it would imply the game will be Mass Effect related.
Update 2: Recall that EA said last February that something "far-reaching" was coming to Mass Effect during the fourth quarter of the publisher's current fiscal year -- or in layman's terms: January 1 – March 31, 2011.
Update 3: Okay, now things are just getting nerdy. BioWare blasted out the adjacent QR code on Twitter which, when decoded, spits out a string of 1s and 0s. When you convert this binary code (we told you: nerdy), it reads: 55.845. Of course, as everyone knows, 55.845 is the atomic mass of iron. Maybe the presence of the word "mass" in our findings isn't quite enough to go on, but we're sure you'll agree that the presence of the word "mass" coupled with a piece of fan fiction titled Mass Effect: Iron Rebirth is practically a smoking M-29 Incisor Sniper Rifle.
Update 4: And another QR code has been loosed upon the unsuspecting people of Twitter. This one is again some binary that translates into: -128.5°F. Converted to Celsius, that becomes -89.16666666666667°C. "The coldest temperature ever recorded on earth is -89.2 degrees Celsius (-128.5 degrees Fahrenheit) at Vostok, Antarctica on July 21, 1983," says Wikipedia; and this Mass Effect wiki page describes the Vostok solar system as "a medium system with four planets and an asteroid belt," itself named after the Soviet "Vostok Program" that resulted in the first manned space flight. Oh, and that asteroid belt that was mentioned? The wiki page calls it a "metal-rich asteroid." You know what else is metal? That's right, iron!
Update 5: A few folks have also written in about the planet Aequitas, which is also from the Mass Effect universe. Logic train: 1st QR code = 55.845, the atomic mass of iron. 2nd QR code = 128.5. -128.5 deg F = Vostok, Antarctica record-breaking temperature. -128.5 deg F ~= -89 deg C = surface temperature of Aequitas, a planet known for its "famous Iron Canyons."
Update 6 11/19/10 5:30pm ET: It's been a couple of days, but BioWare is back at it dropping yet another QR code into the webosphere, this time using Facebook. When read and converted out of binary, this QR reads: "http://www.sis.gov.uk/output/sis-home-welcome.html" which, evidently, is the official site for Britain's Secret Intelligence Service or, as it's also known, MI6. Beyond the two-letter acronym beginning with 'M' and followed by a number format it shares with a would-be ME3, we've got no idea what this means.