I discuss some of the recent
developments in non-equilibrium statistical mechanics: (i) A
non-equilibrium ensemble theory for phase space trajectories, which has
been suggested as a statistical mechanical foundation for phenomena in
shear flows and glassy systems. (ii) A non-equilibrium particle model
with non-Gaussian fluctuations, which leads to singular features in the
distribution of work. By calculating the exact large deviation
function, the work fluctuations are shown to violate the steady state
fluctuation theorem.