2.3 gingerbread - keep screen from dimming down when running certain app?

My 2.3.5 Android phone is set up to dim down the brightness after 30 seconds of inactivity, and shut off and lock the screen after another 30 seconds. After that, I need to unlock the screen to regain access to the running app. I would like to be able to keep a certain app with the screen accessible, while keeping the same configuration for any of the other apps. So instead of having a phone-wide system of brightness dimming, I would like to have an app-specific system. Any ideas?