Abstract: I review the popular idea that at high energies space-time
becomes two dimensional, thereby simplifying the task of quantum
gravity. This seems to be a common prediction in several approaches to
quantum gravity, from Horava-Lifshitz to causal
dynamical triangulations. I then present some recent work on the
cosmological implications of this phenomenon, specifically with regards
to implications for the cosmic microwave background. It turns out that
near scale-invariant fluctuations can be obtained even without inflation
in *all* of these scenarios (with or without violations of Lorentz
invariance). The specific departures from exact scale-invariance, the
bispectrum, and the level of gravitational waves could then be
discriminators among the many different scenarios.