How's this for an amazing practical effect. A speaker generates a 24 hz sine wave that vibrates the water while the camera recording at 24 fps make the stream appear to "freeze". Take it up a notch and it's a slow motion oscillation.
The water only appears this way because of the camera is recording at 24 FPS. In real life there's little to no distortion. What if you set up and array hoses, and cool background. Could be a cheap way to film a sci-fi floating sculpture, or get some nice abstracts. BTW found this via Boing Boing.