Some games have a feature where every x amount of hours, is selects a random gamemode to be the "featured" gamemode. Playing this gamemode rewards players with 1.5x-2x the rewards, getting more people to play that gamemode aswell as encouraging people to get off the slots for once
This would really help for games such as Virus and Little Crusaders as both of those games seem to have little to no servers running ever. It would also give incentive for players to try out new gamemodes they haven't before either because they didn't want to or because there were no servers at the time.
Not sure if this was already planned, but it's just a thought I had