  We consider examples of ``hidden-valley'' models, in which a new confining
gauge group is added to the standard model. Such models often arise in string
constructions, and elsewhere. The resulting (electrically-neutral) bound states
can have low masses and long lifetimes, and could be observed at the LHC and
Tevatron. Production multiplicities are often large. Final states with heavy
flavor are common; lepton pairs, displaced vertices and/or missing energy are
possible. Accounting for LEP constraints, we find LHC production cross-sections
typically in the 1-100 fb range, though they can be larger. It is possible the
Higgs boson could be discovered at the Tevatron through rare decays to the new
particles.
