Yes, they were supposed to be released on the 28th of last month but were delayed. The likely reason is the massive amount of layoffs at Krome Studios.
Anyway, according to Major Nelson, the third set of games for Game Room should release sometime today.
Assuming there haven't been any changes, the third Game Pak will contain the following titles for you to try and buy:
Super Breakout (Atari)
Pitfall! (Activision)
Megamania (Activision)
Night Stalker (Mattel Electronics)
Rack 'Em Up (Konami)
Realsports Volleyball (Atari)
Basketball (Atari)
We’re happy to report the newest #XboxLIVE Game Room titles - including Super Breakout & Pitfall - will be available this Wednesday!
-from Major Nelson's Twitter.