A laser shield on your doors and windows that recognises annoying buzzy clickety insects like flies, moths, and mosquitoes, and kills them before they enter.
Actually, a laser to shoot down mosquitoes exists. It can be programmed to kill only female mosquitoes (as the males don’t bite people).
Is that you John Galt?
Cross kudzu with marijuana.
Threaten drug lords with planting the crossed plant.
Collect $$$. Hope I don’t die in a hail of gunfire.
You know how Apple has Siri, Microsoft has Cortana, Amazon has Alexa? You could call this one “Woman”, so then you could say stuff like “Woman, get me a beer!” or “Woman, bring me a sandwich!” 
My billion dollar idea is a drive-through coffee shop that also sells slices of cold pizza for breakfast. Grab a cup and a cold slice on your way to work!
Please god, tell me you’re a botanist!
When I go to sleep at night, my cat likes to curl up on the other side of the pillow I’m laying on. When he purrs, I can hear it through the pillow. It’s so soothing and always puts me right to sleep.
I’ve often thought, if some one were to make a pillow that purrs, they could make millions.
Nikola Tesla beat you to the punch by about 100 years.
I’d make a portable keychain sized, so you can keep it on your keychain, thumb chopper offer.
This is an awesome idea. One could get their herbal Viagra and redbull all in one stop.
Orgasm-inducing mushrooms.
Granted, not my idea, just a nearby thread title, but I’d imagine it’s a pretty good one.
wellllll, not in all aspects
well then why is it not happening??
Physics.
Good name/post…
A chain of small drive thru produce joints. Apples, oranges, bananas, grapes, carrots, etc. Healthy finger foods for the car to replace the burger stops. Imagine how much healthier those of us who live and work in commuter cities would be!
Design cushioned, padded lightweight cars that are capable of flying in the air (kind of like the Jetsons) and don’t cause any harm if they bump into each other in flight.
Or design a major highway system where cars are placed onto a moving conveyor with each car locked into its own place so people can watch TV, read, or whatever during highway travel. The robot would have to accelerate the car to an acceptably high speed while placing it onto the conveyor.
Bong cleaning service.
Pillow headphones.
Ice-cream delivery.
We could put one right next to my cold pizza and coffee drive-up breakfast kiosk. Let the people choose between the angel or devil on their shoulder.
Electronic de-stimulator for long airline flights. Just knocks you out for the duration. Pills have side effects. Electronics could be controlled by the crew for landings and emergencies.
The universal membership/discount card. Plenti is similar to this, but it only works for those merchants who have signed up.