Bright Idea
The elasticity of a rubber band can be used to move a load in a linear (line) manner by adding potential energy by stretching it, attaching a load to one end, and attaching the other end to a release mechanism such as a clothespin, or a cutable piece to paper, etc.
A rubber band could also be used to produce rotary motion by twisting it as is done on a model airplane. When the prop or wheel is released it will spin using the potential energy stored in the twisted rubber band.

Bright Idea
A spring pulled in tension, or twisted, will release its stored potential energy in the same way as a rubber band.

Bright Idea
A long flat stick has a modulous of elasticity, think of a diving board at the local pool. When you stand on it, it bends, and if you jump on it, it will store and then release the potential energy of your jump and then rocket you skyward.