  We present an efficient and simple modification of the standard transport
algorithm used in explicit eulerian fixed polar grid codes, aimed at getting
rid of the average azimuthal velocity when applying the Courant condition. This
results in a much larger timestep then the usual procedure, and it is
particularly well-suited to the description of a Keplerian disk where one is
traditionally limited by the very demanding Courant condition on the fast
orbital motion at the inner boundary. In this modified algorithm, the timestep
is limited by the perturbed velocity and by the shear arising from the
differential rotation. FARGO stands for ``Fast Advection in Rotating Gaseous
Objects''. The speed-up resulting from the use of the FARGO algorithm is
problem dependent. In the example presented here, which shows the evolution of
a Jupiter sized protoplanet embedded in a minimum mass protoplanetary nebula,
the FARGO algorithm is about an order of magnitude faster than a traditional
transport scheme, with a much smaller numerical diffusivity.
