01 / Zynga >> 
For dominating--and monetizing--the social-gaming industry. The largest social-games developer in the world touts hundreds of millions of monthly active users on FarmVille, Treasure Isle, Zynga Poker, Mafia Wars, and more. But what's truly innovative is its all virtual-goods revenue model: By creating immersive, addicting games, Zynga has roped gamers into paying real money for make-believe "virtual" goods that let them move up in the games or to give their friends gifts. Although small, those numbers add up: Zynga is already profitable, and it's valued at more than $7 billion.
02 / Apple >> 
For developing the year's most successful new gaming platform: the iPad. The tablet has not only sold more than 7 million units since its April debut (and will generate countless more with this month's iPad2 launch), but also fostered all sorts of new mobile-gaming innovation: Doodle Jump, Angry Birds, Enigmo, etc. Apple also made a serious--and smart--move into social-gaming with September's launch of Game Center, a mobile platform that gives multiple users the ability to play on the same app in real time.
03 / Microsoft >> 
For developing the controller-free Kinect. Microsoft wowed with several creations in the past year--a better Bing, the Windows Phone 7--but we're more impressed by what it destroyed: the relevancy of remote controls. Using an assortment of sensors, its hands-free Kinect for Xbox 360 console, which launched in October, reads human voice commands, facial cues, and gestures in the real world (e.g., a punch), and then responds accordingly on-screen (e.g., a video-game knockout). To date, the gaming hit has sold more than 10 million units--more than enough to kick-start its transformation into a full-fledged entertainment platform. Among the forthcoming features: content from Netflux and Hulu Plus, as well as avatars-only virtual worlds for Microsoft's 30 million Xbox Live subscribers.
04 / Valve
For creating Steam, a global digital distribution platform that's quickly becoming iTunes of the gaming industry. Every day, more than six million global unique gamers access the Steam Web app to buy one or more of its 1,200-plus titles, which include computer and videogame blockbusters such as Valve's own Half Life, Portal, and Left 4 Dead. Steam launched in 2006, but in the past year alone, it introduced support for Mac titles and grew its userbase to roughly 30 million accounts.
05 / Facebook >> 
For developing the biggest social-gaming platform on the planet. Facebook's 600 million-plus users have logged thousands of hours playing the likes of Zynga's CityVille (93 million monthly active users) and Popcap's Bejeweled Blitz (11 million monthly active users). With September's launch of Facebook credits--effectively giving the network its own currency--the social-networking titan is also poised to drive the growth of the multibillion-dollar virtual-goods market.
06 / IBM >> 
For its audacious move into serious games. In October, IBM released CityOne--dubbed by bloggers as "SimCity for the real world"--which is the most robust effort to date to solve real-world problems with a game. The free, interactive app targets business leaders, city planners, and government agencies, and touts more than 100 crisis scenarios that require the application of new technologies--most developed and sold by IBM, of course--to create more efficient water use, lessen traffic congestion, and develop alternative-energy sources. IBM's serious-games initiative also extends to education: Students at more than 1,000 colleges and universities around the world tap another IBM sim called Innov8 to practice running virtual businesses.
07 / Rovio
For developing Angry Birds, which has easily been the year's biggest mobile-gaming success story. Since its December 2009 debut, the app--which has users catapult birds to knock down assorted obstacles--has been downloaded more than 30 million times. To capitalize on its own phenomenon, Rovio is launching a line of plush toys, and execs are in talks about a TV/movie deal.
08 / Emotiv Systems
For pioneering the thought-controlled gaming genre. In December 2009, the company unveiled its first commercial product, the EPOC headset, which plugs into a USB port and makes it possible for specially designed computer apps to be influenced by the player's mind and facial expressions. Emotiv recently launched an EPOC app store that now features 7 offerings, including a "Cortex Arcade" game that lets users control Pong paddles with their mind.
09 / Scvngr
For turning everyday life into a game. Building on the "check-in" system popularized by Foursquare, Gowalla, and Facebook Places, this mobile app offers an array of challenges emphasize real user activity. "Fear Factor," for example, gives restaurant patrons points for photographing their food from an odd angle to make it look unappetizing. Since the Google-backed startup's May launch, it has secured 1,000 corporate customers--including 7-11, Coca-Cola, and AT&T--and logged more than 1 million downloads of its iPhone and Android apps.
10 / Nexon
For being the only Asian virtual-goods giant to make inroads in the United States. The company's online games, including Maple Story (more than 90 million players worldwide) and Combat Arms, are bigger than World of Warcraft. Today, more than 30,000 retailers--including Target, Blockbuster, and Walmart--sell prepaid cards with Nexon's virtual currency.
[Photographs by: Art Streiber]