Flossy dice hanging from the mirror. With correct physics calculations. Also air unfreshners (wunderbaum), cd's and micelaneous lucky charms.
Occacional animals and plastic bags on the track s for hazard.
Driver fitness simulation, too long stints gives tunnel vision and sometimes blured vision, this gets worse if you enter the mcdrive often instead of the health food drive through. (full rpg implementation)
Ultimate LFS Ab-tastic home workout system (as seen on TV) FFB will be used to give a workout program. Game will vary parameters like track/car/ffb-prower and stint-length for optimal fat burning. (actually ffb is the only exercise I get so I would prolly use the feature.
Flintstones/tricycle/pedal-car simulator (basicly an oldschool sports game sim where you have to alternate the pedals faster and faster to gain speed). Since its sim you have to measure your pedal stroke & force so it can calculate correct power output, could also be use as a 'push to pass' feature for the UF1 (much like you can speed up a pedal-moped)