Underwater weed wave dynamics I was trying to replicate the dynamic joint setup presented here (Maya) http://youtu.be/quNPwNt5zmk?t=48s (See the first 10 seconds animation of the "Process and inspiration of the making of PTEROIS" starting at 48s). The animation is showing a simple armature dynamic setup waving as you move/rotate the root of the armature around (soft/rigid body kind of dynamics - underwater weed/anemone kind of animation). Is this kind of setup / dynamic animation possible in Blender ? I was unsuccessful to find the proper solution/settings that would give me same smooth, non-jerky, attenuated animation. I used spline IK combined with curve/soft body animation. In the referenced animation note how when the root bone rotates, the rest of the armature follows the root bone propagating the wave all the way to the tail (@note: the tail does not move immediately). 

I'm looking for a solution that would be as close as possible to the illustrated one: namely i want the dynamic wave animation to be smooth, the curve bending should be smooth (no uneven bending due to properly updated curve tangents during the animation). Also the curve should not jump around due to some funky solving errors, and the waving should attenuate to the rest position without further mini oscillations. And the armature should not stretch as the curve animates.
In order to help refine your searches for how to do simulations/animations, here are a few tips and key-words to help you on your way.

For sea-weed, you could start by adding a plane and then also adding a particle system to the plane.
Here I used mostly default settings with the few differences visible in the attached image.


Then I added a Force Field-> Turbulance and animated it's position using two keyframes.



You can also substitute each 'Hair' with a model that is on a separate layer using the following setting.