Ever heard of the Leidenfrost effect?

[BridgeTroll]

Just a cool video... 

http://www.youtube.com/v/w0lMJcAfzU4

[Jason]

That is one of the coolest things I've seen in a long time!

[BridgeTroll]

That is one of the coolest things I've seen in a long time!

I am sure there must be a practical application of it...

[Dog Walker]

Neat video!  The effect is caused by a thin film of steam under the droplet that has the effect of insulating the droplet from the hot surface and making it nearly friction free.

Had never seen the directional effect before.

Red hot drops of metal will do the same thing if they are dropped on a surface with just a little moisture in it.  If you have ever seen welding spatter you have seen it.

[Jason]

That is one of the coolest things I've seen in a long time!

I am sure there must be a practical application of it...

Nothing comes to mind.... though I would love to see some practical application.

Seems to me that using this on any large scale would require a lot of energy to maintain surface temperatures to the metal. 

[Dog Walker]

I could think of an art project where pigment or acids could be added to the water droplets so that trails would be left behind.

This is the sort of thing my friend Brett Waller could do.  He is both an outstanding artist and a skilled mechanic, welder, and all around creative wizard.