http://jalopnik.com/5476893/gallery-inside-forza-motorsport-part-i-the-office//gallery/20
Look at the bottom photos, you can see wet tracks and it looks like the windshield wipers are on. Click the above link to see a bigger photo. The caption also reads, "Art boards for the Crown Jewel and Sedona Raceway Park tracks. Attention, Forza geeks: There is something very interesting about this picture. Can you tell what it is?"