  We present results of a high-resolution imaging survey of barred S0--Sa
galaxies which demonstrate that the central regions of these galaxies are
surprisingly complex. We see many inner bars --- small, secondary bars
(typically less than a kiloparsec in radius) located inside of, and probably
rotating faster than, the large primary bars. These are present in about one
quarter to one third of all our sample. In contrast to some theoretical
expectations, they do not seem to enhance AGN activity significantly. A third
of barred S0's appear to host kiloparsec-scale disks within their bars; but the
frequency of such inner disks is much lower in our S0/a and Sa galaxies. In
addition, we find one example of a triple barred galaxy, and two cases of
purely stellar nuclear rings --- probably the fossil remnants of past
circumnuclear starbursts.
  We comment briefly on results from an ongoing analysis of known double-barred
systems, extending to Hubble types as late as Sbc, and discuss their
characteristic sizes and orientations.
