Acoustic waves have found new utility in microfluidics in recent years, providing an enormously powerful ability to manipulate fluids and suspended particles in open and closed fluid systems. In this talk, we discuss fundamental and powerful concepts of acoustic wave generation and propagation with exploration of new phenomena observed at small scales, particularly in the context of useful applications that illustrate the utility of ultrasound applied to fluid manipulation at small scales. Rapidly rechargeable batteries, atomization technologies for disinfection and pulmonary drug delivery, and observation of cell and organism effects from non-cavitating ultrasound will be discussed. Especially curious physical phenomena at the nano-scale will also be shown, and, along the way, the fascinating underlying physics tying together the acoustics, fluid dynamics, and broader physical phenomena appearing in these systems will be described. Attention will be paid to the fundamentals not often found in the literature in hopes of enabling the attendee to gain enough training to join the burgeoning discipline.