Arduino Shields
XBee’s won’t get you connected to the Internet, but they do provide a solid, cheap means for communicating wirelessly. You could use an XBee to wirelessly trigger coffee machines, sprinklers, lights, or other household appliances.
The self-titled star of this category. This shield is basically a big prototyping area. You can stick a mini-breadboard on top, or just solder directly to the shield’s prototyping area.
This is one of the more classic shields. The Ethernet Shield supplies your Arduino with an ability to connect to the world wide web. There’s a great library to support it as well.
Equip your Arduino with a unique 128x128 cellular phone color LCD.
This classic motor driver shield can control two DC motors.
Turn your Arduino into an MP3 player. Just plug in a µSD card, add some speakers, upload the example code, and you can make your very own MP3 Playing Music Box