title: XNA Change background colour programmatically
body: <p>Is there a way to change the colour/color of the background programmatically and constantly, for example, I want the beginning colour to be perfectly blue (for example), then every <code>Update()</code> call I want the background to slowly change to green, then yellow, then blue etc.... I want the colours to fade in to the next colour and not just suddenly switch.</p>
  
  <p>Any ideas how I can achieve this?  I know there's <code>GraphicsDevice.Clear(Color.CornflowerBlue);</code> but that's obviously not what I want.</p>