Do you mean you would like to hear the CD and see the game (effectively not hearing the game) or do you want to hear both and have independant level control on both? Depending on what receiver you have both options may be possible through the use of a feature called "multizone".
Let us know what receiver you have so we can better steer you in the right direction. It's likely that the receiver you own has multizone capability, as many HDMI audio equipped receivers can do. Just to name a few fairly cost effective receivers that do this; Yamaha RX-V663, Onkyo TX-SR606, Pioneer VSX-1018, Denon AVR-1909, Harman Kardon AVR 254, just to name a few.