Depends on the overnight. Some are reduced rests with as little as about 8.5 hours of rest, in that case, sleep is about all you can do. Some are as long as 22 hours, or even longer than that (like the Skywest coveted Inyokern overnight). In that case, I sleep in, eat a slow lunch, go run, hit the pool, visit the China Lake Naval air museum (pretty cool), eat a good dinner (slowly again), watch TV, then go to work. Most if not all hotels have workout rooms and pools. Also, most hotels do have food nearby, and the hotel van is usually very helpful in driving you to pick something up. However, I can usually pack most of my food in my cooler bag for a trip. Saves money, and also eat alot healthier which is important in this job.