How can one determine the chess configuration that maximizes the number of possible moves?

Question

To clarify, what is the chess-board configuration that would maximize the number of valid moves one player could make on his or her turn? I thought of this question while playing chess, how apropos. I doubt there is a unique configuration, but I am not sure. The problem seems difficult because one must consider every single piece's movement, and the limitations on that piece's movement by other pieces. At any rate, I appreciate any thoughts, hints, or solutions.