Hyperweapon is a game where the primary attack resolution mechanic is shooting a Nerf gun at a target in real life. In-game you're firing superpowered Hyperweapon firearms, in real life, you're using a dart blaster.
Me when I'm giving advice to GMs: okay so the system isn't quite made with that in mind, but I think you can make it work if you're up-front about it being a departure from the baseline. oh also houserule that bit it might get in the way
Me when I'm giving advice to system designers: Break Their Will Beneath The Wheel
Princess Wing awakened a hunger in me for card-based tactical combat systems. Further examples have been limited and/or I keep forgetting when I find them, but I did find a couple cool examples recently