How to make a wiggly animated curve? I'm trying to make a curve move in sort of a worm-like fashion, and I'm not able to get it to move properly with F Curve modifiers.  Basically, I want it to move in a looped "s" shape pattern.  How can I achieve this?

This is the pic; the curves are the yellow beam and the electric forcefield wrapping around it.  I used displacement modifiers for the ripple effect.



Basically, I want to animate the curves in an s-shaped pattern like in Ghostbusters:
Good ol' fashion hook modifier.

One way to set up a hook.

Snap 3d cursor to control point of curve in edit mode, then in object mode add an empty.  With the empty selected, shift select the curve return to edit mode,  and "Hook to selected Object" (from space search).  



Now you can animate the position of the hook to manipulate your curve.  Adding more hooks will give you more control.


Pretty crappy gif, but you get the idea.  The empty is hooked to the right control point of the default bezier curve. The empty is animated to rotate and follow a circular path.