Check this out:
http://www.youtube.com/watch?v=irVW4U8zq_k

That my first proper Arduino test, controlling a 10 LED running light. I attached a small button via interrupt as well to start & stop the light. More to come soon, stay tuned!

Here the (very,very ugly) source code:

[c]
int ledPin = 3; // First LED connected to digital pin 13
volatile int stop = LOW;

void setup()
{
Serial.begin(38400);
for( int i = 0; i < 10; i++) {
pinMode(ledPin + i, OUTPUT);
}
attachInterrupt(0, stopit, RISING); //Button attached to Pin 2
}

int i = 0;
void loop()
{
for( i = 0; i < 7 && !stop; i++) {
blink(ledPin + i);
}
for( i; i >= 1 && !stop; i–) {
blink(ledPin + i);
}
for( i = 0; i < 10 && !stop; i++) {
blink(ledPin + i);
}
for( i; i >= 3 && !stop; i–) {
blink(ledPin + i);
}
for( i; i < 10 && !stop; i++) {
blink(ledPin + i);
}
for( i = 9; i >= 1 && !stop; i–) {
blink(ledPin + i);
}
}

void stopit()
{
delayMicroseconds(1000);
stop = !stop;
}

void blink( int pin ) {
digitalWrite(pin, HIGH);
delay(120 - abs( pin - 8 ) * 20);
digitalWrite(pin, LOW);
}
[/c]