  Light cold dark matter consisting of weakly interacting slim (or sub-eV)
particles (WISPs) has been in the focus of a large number of studies made over
the past two decades. The QCD axion and axion-like particles with masses in the
$0.1\,\mu$eV--$100\,$meV are strong candidates for the dark matter particle,
together with hidden photons with masses below $\lesssim 100\,$meV. This
motivates several new initiatives in the field, including the WISP Dark Matter
eXperiment (WISPDMX) and novel conceptual approaches for broad-band WISP
searches using radiometry measurements in large volume chambers. First results
and future prospects for these experiments are discussed in this contribution.
