Create a roleplaying game in which voice overs are an integral part of play. They might be purely narrative and / or descriptive in nature, the means in which players describe their character’s thoughts, reactions and actions. They could also provide some mechanical advantage in play, perhaps letting players describe their character’s reactions to events or current mental state in return for a bonus to dice rolls. Voice overs would be particularly appropriate for a noir-style game;

“The darkness was particularly menacing in the alley, and I steeled myself for a trap yet to be sprung.”