  We present an experimental study of capillary surfers, a new fluid-mediated
active system that bridges the gap between dissipation- and inertia-dominated
regimes. Surfers are wave-driven particles that self-propel and interact on a
fluid interface via an extended field of surface waves. A surfer's speed and
interaction with its environment can be tuned broadly through the particle,
fluid, and vibration parameters. The wave nature of interactions among surfers
allows for multistability of interaction modes and promises a number of novel
collective behaviors.
