A fake third boob for the middle of a womans back.
For when you’re dancing of course.
Uh none of my ideas are like this… mine is simply to go out during a wonderful summer rainstorm and run around naked…
My younger sister (age 14) came up with the idea for fortune cookies with ridiculous fortunes:
“You will be hit by a flying turd.”
“Be careful, or an elephant may step on your toes.”
You get the idea.
I had this bizarre idea about using ultrasound to track & locate burrows of animals in the mud of marshes and estuaries.
Don’t ask: grad school does strange things to your brain.
I won’t even get started on ideas that came from dreams…
Well, I don’t have great inventions/moneymakers like most of the stuff that’s spinning off from the OP, but I do have weird thoughts.
Whenever I am in a crowd, I start to mentally speculate on the amount of total cash outlay on the clothing for the crowd. How many thousands of dollars are on people’s backs? I also look at people and wonder how carefully they chose their outfit–especially women–and marvel at how much time some of us spend doing that when to other people, they are “just clothes.” You know, you spend hundreds of bucks to get the perfect jeans, the perfect top, and maybe you try outfits on in ten different combinations before settling on the right one, and then the average person would describe you as wearing “Oh jeans, and a yellow shirt.” I just find that freakishly amusing.
This is even more marked for me when I think about wedding dresses. I think about the bride-to-be trooping from boutique to boutique, looking for a dress that has just the right amount of beading, the right amount of puffiness to the sleeve, etc, rejecting one dress because it has a neckline that’s just a tiny bit wrong (in her mind), yadda yadda yadda… and then at the wedding, if you asked the guests? 95% of them would describe the dress as “White with long sleeves and some lace.” All those details totally lost on them.
I mean, we (those of us who care) dress for ourselves and how it makes US feel, but don’t we also think/hope others will notice, either outright or with a “je ne sais quoi” about our marvelous sense of style or hipness? Yet most of them don’t. That’s sort of hilarious.
It appears I was right, someone actually has come out with something similar to, if not the same as, mirrored contact lenses.
Special Effect Contact Lenses
The problem here is we need second opinions. You should set up some clinics where the men can doublecheck the women’s breast exams, and the women doublecheck the testicular exams…
Baloney-grams! That’s right, kids! It’s Baloney-grams!
This happened on my seventh birthday. We were walking down the sidewalk on our way to a pizza place and passed a party store. A sign for Balloon-a-grams caught my dad’s eye. Only he thought it was for Baloney-grams.
Just imagine, the doorbell rings - you answer and some guy hands you a slab of balogna along with Aunt Tillie’s best wishes.
This evolved into Balogna-grahams, the cereal chock-full of balogna goodness. A little nugget of balogna inside a square of cereal. There would be two versions. One plain and the other with freeze-dried cheddar cheese. Instead of prizes, packets of mustard would be included. You could get plain, honey dijon, or hearty deli style. Be the first in your neighborhood to collect 'em all!
Do great minds think alike, or what? I used to want some of these, too. But they would have to be mirrored over the entire visible portion of the eye, not just the iris. Sort of the chrome-spheres-in-your-sockets look. Wear them with mirrored sunglasses, so that when you take them off: “Jinkies, Scoob!”
…and right next door, the sperm donor clinic. 
Market inappropriate gift sets, like the complete works of Sylvia Plath and a pair of oven mitts.
Sitting down for lunch at school last semester and talking about car racing i got an idea to provide drivers with data, sorta like a heads up display but with no display. A small laser sensor would keep track of your eye and when it looked to certain position (like where all the gauges should be) it could beam the info (mph, rpm, fuel and so on)onto the inside of the visor, and when the driver looked back up it would be gone. Im sure it wouldnt be all that difficult to make and could have uses in other disiplines like fighter pilots and so on