  Multi-layer epitaxial graphene (MEG) is investigated using far infrared (FIR)
transmission experiments in the different limits of low magnetic fields and
high temperatures. The cyclotron-resonance like absorption is observed at low
temperature in magnetic fields below 50 mT, allowing thus to probe the nearest
vicinity of the Dirac point and to estimate the conductivity in nearly undoped
graphene. The carrier mobility is found to exceed 250,000 cm$^2$/(V.s). In the
limit of high temperatures, the well-defined Landau level (LL) quantization is
observed up to room temperature at magnetic fields below 1 T, a phenomenon
unique in solid state systems. A negligible increase in the width of the
cyclotron resonance lines with increasing temperature indicates that no
important scattering mechanism is thermally activated, supporting recent
expectations of high room-temperature mobilities in graphene.
