This is one of the first projects I have made with Arduino. It's a little siren with a LED that fades and blinks on and off. It demonstrates basic use of LEDs and speakers. Also check out this article: 8-Pin Programming Shield
Fist off, gather your materials and tools. I am assuming that you known the basics of Arduino and how to solder.
Materials: -Arduino Uno -USB cable for the Arduino (sometimes called a printer cable) -solderless breadboard -breadboard jumper wires -LED (Any color) -A small resistor or two. -small speaker (I found one for $2 at a thrift store) -Ping pong ball