Magnons are the quanta of collective spin excitations, the spin waves, and phonons are the quanta of elastic vibration waves. Over 60 years ago, Charles Kittel proposed that spin and elastic waves would couple by means of the magnetoelastic interaction, enabled by the spin-orbit interaction. Since then, a wealth of phenomena involving the interplay between magnons and phonons have been observed, in an ever-growing research field at the intersection between magnetism, magnonics, and spintronics. In this webinar I will present the basic concepts of magnons, phonons, and their interaction, and three experimental results with theoretical models demonstrating some unique hybridization phenomena, namely: Magnon-phonon conversion in space- or time-varying magnetic field; the spin of phonons created by the conversion from magnons; and phonon pumping by magnonic spin currents.