  The excess of electron-like events measured by MiniBooNE challenges our
understanding of neutrinos and their interactions. We review the status of this
open problem and ongoing efforts to resolve it. After introducing the
experiment and its results, we consider the main experimental backgrounds and
the related physics of neutrino interactions with matter such as
quasielastic-like scattering and weak pion production on nucleons and nuclei.
Special attention is paid to single photon emission in neutral current
interactions and, in particular, its coherent channel. The difficulties to
reconcile the MiniBooNE anomaly with global oscillation analysis is then
highlighted. We finally outline some of the proposed solutions of the puzzle
involving unconventional neutrino-interaction mechanisms.
