According to the official website, an OVA of Mondaiji-tachi ga Isekai kara Kuru Sou Desu yo?
was announced to be released in July 2013. It will be bundled with the eighth volume of the original novel.
Mondaiji TV anime official website
The first episode of the TV anime will be aired on January 11, 2013.
Source: Kadokawa Shoten
Mondaiji-tachi ga Isekai kara Kuru Sou Desu yo? OVA