If it is deemed legal that drivers can actively influence the aerodynamics of the cars (other than ther front wing), how about these ideas:-
Downforce producing helmets that vary the downforce if the driver tilts his head up or down? (infact, less stupidly you could have a vent behind the driver's head which is opened if he leans forward?)
Or how about wings on gloves that the driver sticks into the air stream to alter the flow around the cockpit? -Even better how about gloves which have wings on them that get exposed as the driver turns the steering wheel.. i.e. only coming into effect when the car is in the corners?