My idea is to open a topic where others people can write their own great ideas.
I think this will be my greatest contribution to posterity.

A metal detector fixed to the front door that beeps when you go out without exact change for the bus.

An online store which sells DRM-free games! Oh, wait....

device to extract op soul.

A device to control OPs mind!

Something for detecting the ink level in a non transparent pen without taking out the refill.

I have been working on this one for over a decade.

I plan to invent an earthquake machine to subduct Oregon so I can save 5 hours on the drive from Seattle to San Francisco.

Sorry cecil! :)

You know, it might be easier to get your pilots license and a plane. That also helps your travel time to pretty much anywhere, not just San Fran.

Oh, and side benefit - cecil gets to live.

If you want i can invent a flying machine who travel from Seattle to San Francisco in less time.

Hi cecil!

OMG. Flying is not fun. Inventing earthquake machines is. Geez.

;)

Creating an affordable mini-rockets using electro-magnetic power and solar.

So everybody can send all their garbage to space. and not pollute the earth.

Oh. and you can take space-selfies too.

A language very similar to C# that doesn't compile to byte code and doesn't have a great hulking runtime associated with it.

That's my wet dream, anyway.

(and if anyone is wondering, yes, I've played with D.)

A door mat that blows up no matter who rang.

in czech we are used to say something like "straightener to bender" .)

Watching grass grow and actually having fun at the same time.