Usually parametric oscillations are not the topic of general physics courses. Probably it is because the mathematical theory of this phenomenon is relatively complicated, and until quite recently laboratory experiments for students were difficult to implement. However parametric oscillations are good illustrations of the laws of physics and can be explained qualitatively; by using PASCO equipment, quantitative laboratory experiments can be designed rather easily. Below the following experiments are described: parametric oscillations of a simple pendulum, a vertical spring-mass system, and a stretched string. (Contains 1 table and 6 figures.)