Inspired by this ad, here is how to create the effect of fonts that seem sunk below the surface in PowerPoint 2007 (as shown in the last 2 images).
  1. Choose a background color
  2. Enter text, preferably in a fat font (I used Helvetica Neue Heavy in this example)
  3. Select the text, go to format, text effects, shadows, and pick inner shadow with light from the top
  4. In text effects, pick a text fill that is just slightly darker than the background