This question was cross-posted on Electronics Stack Exchange. Here is my answer from over there:
Exactly what charged particles are flowing outside (and inside) a permanent magnet that create the magnetic "lines"?
The magnetic field of a permanent magnet is not caused by flowing particles.
The electrons within a ferromagnetic material, even if they aren't flowing, have quantum mechanical spin. If the spin vectors of many of the electrons within the material are aligned, they produce a net magnetic dipole moment, producing the macroscopic magnetic field lines associated with a permanent magnet.
(This is just another way of saying, even when electrons aren't moving, they produce a magnetic field. We don't really know "why" that is, but we have a mathematical model of how much field they produce and how it interacts with other objects, and we call that model the "spin" of the electron).
You can read more about this in the Wikipedia article on Ferromagnetism.
Do those particles come from something inside the magnet or does the magnet do something outside of it to affect unknown particles to make the lines?
It comes from the electrons in the magnetic material.
If there is a current (i.e. a continuous flow of charged particles), then why don't we harness that current like a water wheel
Since the magnetic field doesn't derive from the flow of particles, we can't harvest it as if it were a flow of particles.
We measure B in terms of Newtons/meter/Ampere ... Consequently, those "magnetic lines" are currents (or flows) of charges
The B-field has amperes in its units because it produces a force on a moving charge according to the Lorentz law:
$$\vec{F}=q\vec{v}\times{}\vec{B}$$
Since it is multiplied by a charge and a velocity to produce a force, it must have units $\dfrac{[\mathrm{N}][\mathrm{s}]}{[\mathrm{C}][\mathrm{m}]}$
in order for the equation to balance.
Just as a force itself has $[\mathrm{kg}]$ in its units because it has an effect on something with mass, although a force does not have mass itself; a B-field must have charge in its units because it effects charges, not because it is composed of charge or contains charge.
Best Answer
No.
Contrary to what might be intuitive, it does not take energy exert force. You might be tempted to think that magnet "gives" your weight some energy by pulling it. While the weight would indeed have more gravitation potential energy, it would also have less magnetic potential energy.
In other words, you have to do the work to remove the weight from the ceiling, the magnet won't simply drop it just because you want it. :)
Permanent magnets can lose some of their magnetism over time, but this has nothing to do with the conservation of energy.