Since Model S is aware of its position, what's around (sorta), and when it's charging, why not make a game out of this? It shouldn't be hard for the computer to monitor when you do certain things and award you "points" for your "accomplishments". I was thinking that there should be levels for each achievement (bronze, silver, gold, platinum, diamond?) based on powers of two (digial counting, for 2/4/8/16/32) times/minutes/iterations/visits.
So how about this: the nav knows where all national and state parks are. Actually it could know about just about anything Google knows about. So when the car powers off, it checks where it's at and if the place you parked is reasonably close to a certain type of place: parks, supercharging stations, national monuments, various sight-seeing spots. You get points for the visit if you're there for at least, say, 30 minutes.
There's also a lot of info the car has on driving characteristics. So how about points for sustained kW/mile values? How about travelling at constant 55MPH for certain amounts of time? How about achieving certain distances on a single charge? How about recharging the battery from < 10% to > 90% some number of times?
There are so many possibilities! This could make driving a lot of fun, and give people bragging rights. After all, the car is internet-connected, and can update an online scoreboard with a user's point accumulation (if opted in).