Buy this 37 in 1 - kit.
7 color flashing LED module automatically uses 5mm round high-brightness light-emitting diode which has the following characteristics:
/*
Blink
Turns on an LED on for two second, then off for two second, repeatedly.
This example code is in the public domain.
*/
void setup () {
// Initialize the digital pin as an output.
// Pin 13 has an LED connected on most Arduino boards:
pinMode (13, OUTPUT);
}
void loop () {
digitalWrite (13, HIGH); // set the LED on
delay (2000); // wait for a second
digitalWrite (13, LOW); // set the LED off
delay (2000); // wait for a second
}