Abstract: A fluid user interface is presented for applications such as immersive multimedia. In one embodiment, one or more sprays or jets create an immersive multimedia environment in which a participant can interact within the immersive multimedia environment by blocking, partially blocking, diverting, or otherwise engaging with a fluid, to create computational input. When the fluid is air, a keyboard can be implemented on cusions of air coming out of various nozzles or jets. When the fluid is water, the invention may be used in environments such as showers, baths, hot tubs, waterplay areas, gardens, and the like to create a fun, playful, or wet user-interface. In some embodiments, the spraying is computationally controlled, so that the spray creates a tactile user-interface for the control of such devices as new musical instruments. These may be installed in public fountains to result in a fluid user interface to music by playing in the fountains.