  We construct, using geometric invariant theory, a quasi-projective
Deligne-Mumford stack of stable graded algebras. We also construct a derived
enhancement, which classifies twisted bundles of stable graded
A-infinity-algebras. The tangent complex of the derived scheme is given by
graded Hochschild cohomology, which we relate to ordinary Hochschild
cohomology. We obtain a version of Hilbert stability for non-commutative
projective schemes.
