Zynga, the company behind such social gaming hits as Farmville, Cityville, Mafia Wars and Words With Friends, launches its IPO today. That includes 100 million shares at $10 a piece.

That values the company at over a billion, and is even bigger than even Groupon’s IPO earlier this year. It is actually being called the biggest tech IPO since Google.

Interestingly, CEO Mark Pincus elected to ring the opening bell at at its own headquarters in San Francisco, as opposed to the New York Stock Exchange.

@zynga
ZyngaWe just pushed the button to open the NASDAQ at our HQ in SF. #zynga 2 minutes ago via CoTweet · powered by @socialditto

In its regulatory filing, Zynga indicated it would offer about 14% of its common stock. According to Wall Street Cheat Sheet, Zynga doubled sales to $829 million in the first nine months of 2011.

Much is being made of all of the talent Zynga has been able to steal away from other companies. According to Business Insider, citing data from LinkedIn, they managed to “poach” 200 employees from rival game maker Electronic Arts alone, including 8 top executives.

Zynga is trading on the NASDAQ under the symbol ZNGA.