  PKS 1257-326 is a quasar showing extremely unusual, rapid interstellar
scintillation (ISS), which has persisted for at least a decade. Simultaneous
observations with the VLA and ATCA, combined with ATCA monitoring over several
years, have revealed some properties of the turbulent ionized medium
responsible for the ISS of PKS 1257-326. The scattering occurs in an unusually
nearby (~10 pc), localized "screen". The scintillation pattern is highly
anisotropic with axial ratio more than 10:1 elongated in a northwest direction
on the sky. Recent findings and implications for small-scale ionized structures
in the ISM are discussed.
