TITLE: How to see the Phase Space of a Physical System as the Cotangent Bundle
QUESTION [30 upvotes]: Two things today motivated this question.
First, the professor said that in a lecture Thurston mentioned

Any manifold can be seen as the configuration space of some physical system.

Clearly we need to be careful here, so the first question is 

1) What is a precise formulation and an argument to see why the previous statement is true.

Second, the professor went on to say that because of the Poisson Bracket, we see the phase space of a physical system as the Cotangent Bundle of a manifold. I understand that we associate a symplectic form to the cotangent bundle, and that we want to think of Phase Space with a symplectic structure, but my second question is

2) Could you provide an example of a physical system, give the associated "configuration manifold" show the cotangent space, and explain why this is the phase space of the system.

I pushed the lecturer quite a bit to get this level of detail, so pushing much further would of probably been considered rude. I should also mention he is speaking about these things because we want to quantize the geometry associated to this manifold. So he looks at the cotangent space which apparently has a symplectic structure, and sends the symplectic form to the Lie Bracket. If any of the things I have said are incorrect, please comment with corrections. I am just learning this material and trying to understand how it fits with my current understanding. 
One last bonus question(tee hee),

If your manifold is a Lie Group, we get a Lie algebra structure on the Tangent Space. Is there a relationship between this Lie Algebra structure and the one you would get by considering the cotangent space and then quantizing in the fashion of above?

Thanks in advance!

REPLY [4 votes]: I don’t have the rep to put this in a comment where it belongs, but wanted to note that TM has a canonical structure analogous to the canonical 1-form of T*M: the “Lagrangian” or vertical vector field. Rather than write a formula, let me explain it intuitively. Any vector space V when viewed as a manifold is naturally isomorphic to the tangent space TV(v) at any point v. Therefore, we can take the (vertical!) tangent space at any point in the fiber of TM over x, and identify it with the fiber itself. If at each point in the fiber TM(x) we choose the tangent vector in T(TM(x)) naturally identified with that point, we end up with a vertical vector field defined on all of TM. With this natural structure in hand, you can now proceed to geometrize Lagrangian mechanics.