Social media gaming giant Zynga Game Network Inc., which is responsible for games such as “FarmVille” and “Mafia Wars,” has acquired Challenge Games Inc., an Austin gaming company co-founded by longtime entrepreneur Andrew Busey.

The move creates a local presence for Zynga, which has a list of hit games. Both “FarmVille” and “Mafia Wars” have been popular on Facebook and spawned a new category of game — one that’s more casual, free to play and uses social media as a platform.