  Horava gravity is a relatively recent (Jan 2009) idea in theoretical physics
for trying to develop a quantum field theory of gravity. It is not a string
theory, nor loop quantum gravity, but is instead a traditional quantum field
theory that breaks Lorentz invariance at ultra-high (presumably
trans-Planckian) energies, while retaining approximate Lorentz invariance at
low and medium (sub-Planckian) energies. The challenge is to keep the Lorentz
symmetry breaking controlled and small - small enough to be compatible with
experiment. I will give a very general overview of what is going on in this
field, paying particular attention to the disturbing role of the scalar
graviton.
