In the lattice QCD approach to hadron spectroscopy one can extract
finite-volume stationary-state energies, including excited states, from
temporal correlators.  Probe interpolating operators from correlators
which are estimated via Monte Carlo integration: these operators create
single- and two-hadron states with spatially displaced quarks, with an eye
towards possible tetraquark states.  Studies of dynamical quarks in SU(3)
gauge theory on large lattices with near-physical pion masses are made
possible by new techniques in operator smearing and stochastic estimation
of quark propagators.  Given the spectrum in finite-volume, the Luscher
method allows one to relate this to infinite-volume resonances; recent
results include the rho resonance in pion scattering, on a large 32^3 by
256 lattice at a heavy pion mass of 240 MeV.