S550: Nightlife Mood Activated!
Another of the ridiculous/amazing features offered on the S Class is the "interior cabin fragrance" system, which is part of the AIR-BALANCE (Benz words must be in all caps, apparently) system.
AIR-BALANCE has three features: an "enhanced" air filter, an "oxygen ionizer," and the fragrance system. While this had its debut in the S Class cars, it's now an option across the Mercedes line. If you want more about the fragrance design process, the perfume enthusiasts have the full story for you. In typical Mercedes fashion, they've worked hard to make the scent subtle, ensuring that it doesn't cling to your clothes or the upholstery in the car (heaven forfend!).
My S550 came with an (empty) canister of the "Nightlife Mood" scent installed in the glovebox (right next to the Grey Poupon). So, to better have the full S Class experience, I replaced it with a new fragrance "flacon" (yeah, they ain't cheap). I'm looking forward to my frangrance-enhanced #SClassLife.