Superfluids

Pretty interesting, here's a video of the superfluid effects of helium: LINK

quote:

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Superfluidity is the characteristic property of a fluid with zero viscosity which therefore flows without loss of kinetic energy. When stirred a superfluid forms cellular vortices that continue to rotate indefinitely.

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Wikipedia entry

Once it achieves the superfluid state the liquid helium leaks through the container that ordinarily would hold it. It can also travel up the sides of a container and can create a fountain that never stops.