The electrons and holes in a graphene sheet behave very much like a relativistic liquid. As a consequence, the properties of thermo-electric transport of this fluid of interacting Dirac fermions are rather peculiar. At small doping and high temperatures, graphene exhibits many signatures of a quantum critical system: the inelastic scattering rate is set only by the temperature, and the conductivity assumes a nearly universal value, solely due to electron-hole friction. In this regime we find pronounced deviations from standard Fermi liquid behavior and a peculiar collective cyclotron resonance in the frequency dependent response. Some of these results have been anticipated by a relativistic hydrodynamic theory, and are fully confirmed by Boltzmann transport theory for weak coupling. Most interestingly, similar results are also found in the case of certain strong coupled liquids which can be solved exactly by the AdS-CFT correspondence. Moreover, in that context it is interesting that undoped graphene turns out to be a nearly ideal fluid with an anomalously small electronic viscosity, very similar to recent observations in the ultra-relativistic quark gluon plasma. I will also discuss possible consequences of the low viscosity for electronic transport in clean graphene.