I've wondered the same myself. I think They're setting a color of white with 0.4 alpha on the font and a color of black with 0.4 alpha on the background. They overlay the whole thing over a gaussian-blurred and saturated image of what was previously behind the today view.
So the required steps to produce the same effect would be something like the following:
1. Grab background image
2. Blur and saturate image
3. Add below the current view
4. Set black background of 0.4 alpha and white font of 0.4 alpha on the current view.
If you can think of a way to make the background translucent right behind the font that would make the color show more.
Here's an image of what that would look like (including the translucent background behind the text). I did this real quick in photoshop, don't mind the font.
Hope this helps!