I wrote over in IMHO, this what I felt was a brilliantly funny and spectacular invention:
I dare say, this could be one of my finest inventions yet.
Sold! When can I expect delivery?
You know, while I like the long-distance sex shop call idea, I’d actually be just as happy if we could forward telemarkers’ calls to other telemarketers. 
But what do cats have to do with it?
Assuming you’re not feeding her a straight line, it’s a reference to the French word for four, “quatre.” It’s pronounced rather like the word “cat” but with a tiny “r” sound at the end - vaguely like you’re going to say “catch” but stop yourself during the last consonant sound. Look at her odd numbering system for the other inventions.
Ah, I see. Not being a native English speaker, I’m unfortunately not as sensitive to auditory jokes as you guys.
Ferret Herder is correct!
I also, being the whore that I am, thought I would lure those that are slaves to their cats into this thread, thus bolstering my numbers to this thread, instead of the usual *5 people have looked at your thread and have decided to let it drop like a stone to the bottom of eternal obscurity. *
I also resurrected this thread subject to see if any of the newish dopers have any brain storms that they know would sell like hot cakes if only they were not held back by a lack of engineering, advertising & financial backing along with zero motivational skills.
I just wish they’d put brake lights on the fronts of cars, so I don’t get a heart attack when someone comes up behind me really fast – I’d be able to tell that they were actually braking.
Also, it seems to me that if there were brake lights on the front of cars, a number of different types of accidents (or maybe just inconveniences) could be avoided - that whole “Are you going? Okay, I’ll go - oh, you are going,” thing, both at intersections with other cars, and with cars slowing down/stopping for pedestrians.
I also wish someone would make a periscope-type device for cars, so that I could see around the parked cars when I’m trying to turn onto another street.
And last, but not least, I think a second set of wheels – parking wheels – should be invented. These would be perpendicular to the curb, and retractable. When you need to parallel park, you pull up to the spot and activate the parking wheels. They come down, lift the regular wheels slightly off the ground, and let you just scoot right into that spot. No more backing-and-filling! (Okay, I’m sure there would be problems with this idea. But I’m not an engineer, so I don’t have to deal with them. I just get tired of parallel parking all the time!)
To keep with the car theme:
There should be a waving hand in the back of the window.
To give a thank you wave to someone who let you in in traffic and a one fingered salute for the buttmunches who tailgate.
Cars again:
A mechanism for shining a really bright light back into the eyes of somebody tailgating your car. Or who just has those incredibly annoying super-bright headlights.
MLS, they’re called “Spotlights”. You can get a portable one with about 500,000 candlepower for, oh, $20 around here.
It’s also incredibly illegal, and dangerous, to shine it at someone who’s tailgating you.
Not that I let that stop me. q;}
Shirley, a friend of mine used to keep a glove, with three fingers conveniently bent back, on the rear window windshield wiper (do those things have names?) of his car. Much fun flipping the switch and watching the finger wave back and forth at people ensued.
Ok, my idea: Brake lights that show how much braking is going on!
No really… make 'em like those groovy lights you see on graphic equalizers (stereos, you know).
If you’re not using the brakes, or if it’s night time and just the lights need to be on, there’s just one bar.
If you put your foot on the pedal, but don’t really press, there’s a second bar… showing, ok people behind me, I’m thinking about stopping. Not doin’ it yet tho, just lettin’ ya know.
If you’re putting a little bit of pressure on the brakes, there are I dunno maybe 2-3 bars, indicating how hard you’re stopping. The more pressure you apply, the more bars light up.
If you slam on the brakes, they ALL come on, with a flashing one at the top or something, maybe a new color? The “Oh CRAP I’m stopping NOW, look out!” warning we so desperately need on today’s highways.
If you add something like this, since we know regulations wouldn’t let you completely replace the current system, why not just add it to all four corners of the car? Let everybody know.
Heck, while we’re dreaming, wouldn’t it be cool to have lights that show acceleration too? Why not turning? Heck, you could put a ring of LEDs around the car, that do all sorts of things…
A few years ago, when I moved into my current classroom, I inherited a bunch of stuff. Among the books on how to prevent my students from becoming involved on the wrong side of the Red Scare was this little fifty page booklet, titled something like “Blood on the Pavement” but not, published back in the late fifties or early sixties. I read through it, because how could you not?
Anyway, the author had a section that included improvements he’d like to see, such as periscopes, front brakelights and regular brakelights that would indicate the degree of ‘stoppitude’. I thought the periscope idea was dorky beyond belief (you should have seen the illustration) but that was before giant SUVs roamed the land. Now I’d kill for a periscope. I’m going to find that book and see what else he was ahead of his time about.
As for me, I want moveable sunscreens. You could move the area you wanted shaded around by touching the windshield and dragging to whatever position you desired. Good for bright lights at night, too. And all the windows could go solid when you were parked.
And a dummy light for low tire pressure.