There is a nice explicit description, in <a href="http://dx.doi.org/10.1090/S0002-9939-1984-0722406-4">this paper of Morrison and Stevens</a>, of four dimensional cyclic quotient singularities that are Gorenstein and terminal (cf. <a href="http://mathoverflow.net/questions/45818/resolution-of-singularities">this MO question</a>---terminal implies the non-existence of crepant resolutions).