We describe a series of demonstrations which illustrate the role of the Rayleigh-Taylor instability in everyday events and geophysical flows. Growth of ripples at the water-over-air interface is the basis of this fluid instability, which is the reason for the spilling of water from an inverted jar. This low-cost demonstration has been performed successfully for grades five through graduate school, as well as for the scientific community. Rayleigh-Taylor activities serve as a gateway for further discussion of fluid properties, including pressure, density and surface tension. Our talk will include actual demonstrations and discussion of everyday engineering applications.