Generic multi-button controllers are the most common input devices used for video games. In contrast, dedicated game controllers and gestural interactions increase immersion and playability. Room-sized gaming has opened up possibilities to further enhance the immersive experience, and provides players with opportunities to use full-body movements as input. We present a purpose-centric approach to appropriating everyday objects as physical game controllers, for immersive room-sized gaming. Virtual manipulations supported by such physical controllers mimic real-world function and usage. Doing so opens up new possibilities for interactions that flow seamlessly from the physical into the virtual world. As a proof-of-concept, we present a 'Tower Defence' styled game, that uses four everyday household objects as game controllers, each of which serves as a weapon to defend the base of the players from enemy bots. Players can use 1) a mop (or a broom) to sweep away enemy bots directionally; 2) a fan to scatter them away; 3) a vacuum cleaner to suck them; 4) a mouse trap to destroy them. Each controller is tracked using a motion capture system. A physics engine is integrated in the game, and ensures virtual objects act as though they are manipulated by the actual physical controller, thus providing players with a highly-immersive gaming experience.