This basically does the same thing as the Blinky tutorial, but it uses a Timer object with a callback method to turn the LED on and off.
Here's the code. If you think of any cool variations, please share.
using System;
using System.Threading;
using Microsoft.SPOT;
using Microsoft.SPOT.Hardware;
using SecretLabs.NETMF.Hardware;
using SecretLabs.NETMF.Hardware.Netduino;
namespace BlinkyTimer
{
public class Program
{
const int blinkPeriod = 250;
static bool ledState;
static OutputPort led;
public static void Main()
{
// Set the initial state of the LED to off (false).
ledState = false;
led = new OutputPort(Pins.ONBOARD_LED, ledState);
// Create a System.Threading.Timer instance and pass it the timer callback method.
Timer blinkTimer = new Timer(
new TimerCallback(BlinkTimerCallback),
null,
blinkPeriod,
blinkPeriod);
Thread.Sleep(Timeout.Infinite);
}
public static void BlinkTimerCallback(Object obj)
{
// Invert the previous state of the LED.
ledState = !ledState;
// Set the LED to its new state.
led.Write(ledState);
}
}
}
Thanks again, Chris! 
