Simple Rainbow code (C#)

[649]

1st add timer on (form only)

private void timer1_Tick(object sender, EventArgs e)
{
this.label1.ForeColor = Color.FromArgb(r.Next(0, 255), r.Next(0, 255), r.Next(0, 255));
}

[403]

Make a timer or a while(true) - Loop and put the following in it.

         Random r = new Random();
         Label1.ForeColor = Color.FromArgb(r.Next(0, 255), r.Next(0, 255), r.Next(0, 255));

Change Label1 to whatever your wanting to change the color of.