Adsorbate vibrational excitations on insulator surfaces can be very long-lived if the adsorbate frequency is much greater than the Debye frequency of the solid. This allows time for vibrational excitations to resonantly hop among neighbors a great many times before de-excitation. Sometimes this will result in two adjacent adsorbate molecules both excited to v=1. As a result of anharmonicity, the state with one molecule in v=2 and one in v=0 has a slightly lower energy than both molecules in v=1. Similarly, 3 quanta of vibration shared by two neighboring adsorbate molecules produce a lower total energy if all 3 quanta reside on one of the neighbors. This produces a driving force for "pooling" of energy into highly excited molecules. This effect has been demonstrated dramatically by George Ewing and coworkers@footnote 1@ who observed population of vibrational levels as high as v=15 for CO on NaCl. We have developed a perturbation theory approach to calculate all of the operative rate processes; vibrational relaxation, resonant hopping, pooling, and radiation. We have used these rates in a kinetic Monte Carlo simulation of the energy pooling process. Our results are in qualitative agreement with experiment, and reveal interesting phenomena such as self-trapping and Ostwald ripening. In addition, we predict an enormous C-12/C-13 isotope effect. @FootnoteText@ @footnote 1@ H.-C. Chang and G. E. Ewing, Phys. Rev. Lett. 65, 2125 (1990).