LED blink
LED swing
7 segment LED display
switch
transmissive optical sensor
hall sensor (magnetic switch)
parallax ping sensor (distance sensor)
4N35 optocoupler (turning ON/OFF other low voltage devices/toys)
TRIAC (switching ON/OFF an AC lamp)
IRLD024 MOSFET (switching ON/OFF a 12 volts lamp)

potentiometer (variable resistor)
photoresistor (light sensor)
force resistor (force sensor)
sharp GP2D12/120 ranger (infrared distance sensor)
infrared ranger sensor & light (visualizing ranger distance measurement with LEDs)
piezo film (vibration sensor)
light controller (potentiometer light controller)
stretch sensor & light (controlling an LED intensity with a stretch sensor)
microphone (sound sensor)
TEMT6000 ambient light sensor sparkfun breakout
LED fade (PWM output)
responsive light (analog input/PWM output)

74LS595 Shift Register
micromag 3-Axis magnetic field sensor (ISP protocol)
sensirion SHT15 humidity/temperature sensor (serial 2-wire protocol) sparkfun breakout
sensirion SHT11 humidity/temperature sensor (serial 2-wire protocol) parallax kit

serial input + Processing
serial output + Processing
advanced output
parallax RFID reader
sparkfun USB weather board (barometric pressure, temperature and humidity sensor)

servo motor
multiple servos
servo/analog input (controlling a servo shaft position with a potentiometer)

hello matrix (controlling an LED matrix)
sprite animation (playing an animation on an LED matrix)

digital potentiometer
master reader
master writer
slave receiver
slave sender
SFR08/SFR10 ultrasonic ranger reader (ultrasonic distance sensor)
HMC6352 compass heading (degree resolution compass heading) sparkfun breakout

read serial (touch sensor)

DC motor
teac stepper motor
vibration motor (cell phone motor)
picobotics picopic servo controller (multiple servo controller board)