Only one game announced so far, but it has been confirmed that our next Games for Gold freebie will be the XBLA title "Might & Magic: Clash of Heroes".
The game is 1.44 GB, but also features some freebies, as well as paid DLC.
Given the trend, it should be available on October 1st.
I'll be sure to update this with the October 16th release as soon as I find out what it is~.
Game #2 on October 16th will be Halo 3.