When I worked at Computer City, an old woman called looking for a replacement foot pedal for her Apple IIe.  We later found out that she was used to the way sewing machines work and was actually mousing with her foot, and we got a good laugh out of this - until we realized that the Apple IIe mouse only had one big-ass button on it and, if you learned like she did to mouse with your foot, you had both hands free at all times to type.