This was fun. I hooked the servo up first with a potentiometer and then the pressure sensor. The pressure sensor was more fun to play with, since the potentiometer was limited in speed by how fast I could turn the dial. It is significantly faster to change pressure in between two fingers than it is to turn a dial. Here are 2 videos of each sensor:
(I added post-it flags to the servo for dramatic effect)
potentiometer
pressure sensor
Intro to Physical Computing 