  We propose a new class of phenomenological models for dynamic glass
transitions. The system consists of an ensemble of mesoscopic regions to which
local energies are allocated. At each time step, a region is randomly chosen
and a new local energy is drawn from a distribution that self-consistently
depends on the global energy of the system. Then, the transition is accepted or
not according to the Metropolis rule. Within this scheme, we model an energy
threshold leading to a mode-coupling glass transition as in the p-spin model.
The glassy dynamics is characterized by a two-step relaxation of the energy
autocorrelation function. The aging scaling is fully determined by the
evolution of the global energy and linear violations of the fluctuation
dissipation relation are found for observables uncorrelated with the energies.
Interestingly, our mean-field approach has a natural extension to finite
dimension, that we briefly discuss.
