Quantum gravity is a difficult creature to observe, as its natural habitat resides at the Planck scale, at energies far beyond those currently accessible. Fortunately, it may leave subtle footprints in the form of violations of Lorentz invariance (LIV), which, thanks to various amplification mechanisms, can manifest in the behavior of very high-energy astroparticles. In this talk, we will review some of the main phenomenological consequences of LIV, as well as the alternative scenario of a deformation of special relativity (DSR), in the observation of very high-energy neutrinos and gamma rays.