The first NXT robot I built it’s about the same that paper manual show.
I added a touch sensor on the arm, I raised ultrasonic sensor (now it work better). I maked also some other little changes too.
 
Here the connections list:
 
PORT

DEVICE

A

Arm Motor

B

Right Wheel Motor

C

Left Wheel Motor

1

Touch Sensor

2

Audio Sensor (Microphone)

3

Forward Light Sensor

4

Ultrasonic Sensor (Distance)
 
The first program (pic 2) simply read light sensor (other version read also the ultrasonic) to show on display.
The second program (pic 1, but use this link to see it better: http://www.tonigreco.it/_xna_/download.asp?name=FindHitRedBall.jpg), after an audio command, make robot advances until it’s near to the ball, then it try to center on it (to see better its color), then it try to hit the ball.
You can also see the movie of second program:
 
MINDSTORMS Projects: