Motivated by recent mathematical developements in non-commutative Donaldson-Thomas theory, we construct a new statistical mechanical model of crystal melting to count BPS bound states of D0 and D2 branes on a single D6 brane wrapping an arbitrary toric Calabi-Yau threefold. We also discuss the wall crossing phenomena, which are crucial for the proper understanding of the relation between the crystal melting and the topological string theory.