Ooblek 2.0

LiveLeak.com - Cornstarch Monster on a Speaker

Non-Newtonian fluids are a staple in elementary (and high-shool) science classrooms.  I think one of the driving forces behind good science is a child-like (but not childish) wonder at the world.  It's a desire to tinker and experiment and get your hands dirty.  And it's an appreciation of counter-intuitive things that just look cool.

Also worth taking a look at ferrofluids. You can see a video here.

And at surface tension in oil streams.