A reversible sterilization device, fitted to all children when born. If, one they are adults, they want kids, they have to sit in front of a panel of police, social work, health and education people to justify this and, if successful in their application, they can have the sterilization reversed.
I’d also reinvent the calendar so we had an eight day week with three day weekend. The extra day would be called Rideday.
A hair brush that has a colour/highlights option, so as you brush your hair, it could put any colour in you wanted or high/low lights whatever that last a day or so, or when you wash it out.
