Ability to automatically go active when a certain program is running

There are some fullscreen games that don't seem to prevent Gnome from believing itself to be idle. Thus, the screensaver eventually activates. Perhaps Caffeine can help? It could check every minute or so to see which programs are running, and if one particular program is there, it could automatically prevent the screensaver and powersaving modes from activating. This would require some kind of configuration screen, and perhaps the tooltip for the applet would have to change in case the user was confused about why Caffeine had activated.