Stretch a rubber band over the top of a paint can and use it to wipe excess paint from the brush
Coming in and out with your hands full? Loop a single rubber band around a door's inside and outside knobs, twisting it as you do so that the "X" presses the latch open. Once finished, hang the band on the inner knob for the next time.
Take an old vase, place rubber bands around it, and spray paint it white...what an awesome idea!