This video shows how Travis Pastrana, a recent NASCAR convert, uses the sim to enhance his pre-race regimen, while highlighting some of the other Cup drivers that also use the sim to keep their skills sharp and fresh.
It's a 25-minute video, and the first three minutes are a trailer for Pastrana's upcoming Nitro Circus 3D movie, but if you're looking to see how the pros use sims to inform their driving and their car setup, or just to see that all that time you spend on sim racing isn't wasted, it's well worth the run time.