  Motivated by the physics of graphene, we consider a model of N species of 2+1
dimensional four-component massless Dirac fermions interacting through a 3D
instantaneous Coulomb interaction. We show that in the limit of infinitely
strong Coulomb interaction the system approaches a quantum critical point, at
least for sufficiently large fermion degeneracy. In this regime the system
exhibits invariance under scale transformations in which time and space scale
by different factors. The elementary excitations are fermions with dispersion
relation omega ~ p^z, where the dynamic critical exponent z depends on N. In
the limit of large N we find z=1-4/(\pi^2 N). We argue that due to the
numerically large Coulomb coupling, graphene (freely suspended) in vacuum stays
near the scale-invariant regime in a large momentum window, before eventually
flowing to the trivial fixed point at very low momentum scales.
