Today, Microsoft announced via Xbox Wire that the “limited-time program” is now an ongoing program:

At E3 2013, we launched Games with Gold as a limited-time program to thank our Xbox Live Gold members. Within that short period of time, we’ve seen an overwhelming response, with more than 120 million hours played with Games with Gold titles. Today, as a part of the “Week of Xbox Live,” we’re excited to announce that we are making Games with Gold an ongoing benefit for Xbox Live Gold members on Xbox 360.

Whether they are blockbuster AAA or popular arcade titles, Games with Gold continues to offer a diverse mix of games with two free Xbox 360 titles a month – yours to keep and at no additional cost. According to recent surveys, 97 percent of participating members have given their stamp of approval for Games with Gold, and we’re excited to continue bringing you great games every month as part of our ongoing commitment to providing great value on Xbox 360.