Servo motors are the easiest output device to make motion with a microcontroller. Most common servo motors (like the one some of you got in the kit) can turn 180 degrees, providing huge range of motion that can allow for different types of movements with the help of different physical mechanisms. Read more about servos using this Sparkfun guide.
Next, follow this example to hook up a servo, and drive it directly from an Arduino board. Try adding a sensor or potentiometer to it, like in this Sparkfun guide. Note any question or issue in your blog.
Note: Not all servos have the same wiring colors. Check the specifications on your particular servomotor to be sure.