Two papers for now....
cond-mat/0608069 - Zhou et al., First direct observations of Dirac fermions in graphite
This paper is also in press at Nature Physics. The authors take angle-resolved photoemission spectroscopy (ARPES), and apply it to high purity graphite. ARPES is a very impressive technique - a really nice (highly collimated, bright, well-controlled energy - like from a synchrotron) x-ray beam is incident in a carefully controlled geometry on a sample, and the photoelectrons kicked out of the material are detected in an angularly resolved way. Applying conservation of momentum and energy lets one use this method to extract (2d) band structure information about the material. In high Tc compounds, for example, ARPES has contributed greatly to the understanding of "Fermi Arcs" and so forth. Anyway, these folks look at graphite, and find that massless Dirac fermions really do describe well the 2d band structure of this material. They also see some "boring" carriers in there, with parabolic dispersion (that is, energy proportional to the square of carrier momentum, indicating that the effective mass is a well-defined concept). Finally, they see signs that impurities and defects lead to electrons sitting in there. So, the electronic transport physics in this stuff is "rich", meaning very complicated. This is a good example of applying a highly refined tool to a new (yet very old) material system.
cond-mat/0608159 - Sellier et al., Transport spectroscopy of a single dopant in a gated silicon nanowire
The authors here have done a very elegant experiment. They've taken doped Si on insulator, and etched it to form an "island" with source, drain, and gate leads. That island contains a single dopant atom, and by performing low temperature conductance measurements, including significant magnetic fields, they've been able to look at two charge states of that single dopant, and compare with long-held models (D0 and D- configurations) of how dopants sit in Si. The single arsenic donor acts like an extremely small quantum dot, having electron addition energies exceeding 15 meV. This is the kind of experiment that is conceptually simple, but actually doing the work has real experimental challenges.