I conceived of some of these specifically to enter into the Staples Invention Quest contest (none won). The contest was clearly looking for something along the line of Post-It Notes, i.e. cheap, ordinary, useful, and potentially as universal as bacteria. So remember, thinking small is the order of the day...
Safety Marker Pen
Rug Wheels for Office Chairs
Tactilely-Distinguisible Dashboard Controls
You should be able to tell one knob from the other without having to look down. Have you ever been zipping down the highway, funbling around the bottom of the dash to turn down the radio but turned up the AC instead? Then you looked down to find the right knob and almost rear-ended a truck at 65mph? I want my radio volume control to be all knobby like an acorn cap; I want my vent control to be shaped like a bunny; I want my AC knob to feel like velcro hook. No more fumbling, no more terrifying glances away from the traffic.
Crowd Counter Balloon
Camera with Frame-Shaped Laser Sight
UV Taggants for Recycling Plastic
Plastics can be sorted automatically even when broken into fragments.
Mix a unique UV-flouresecent chemical signature into each type of recyclable plastic during manufacture. Then when the containers are disposed of, the recycling center spreads them out on a conveyor where a high-speed pick-and-place robot shuffles everything off to one side that fluoresces a particular, signature frequency vector. This also distinguishes plastics from other impurities such as paper and metal. The signature frequency vectors can be linearly independent so that even if the plastic is ground to dust, a machine can tell what combination of plastics the dust is made of (at a glance) and dispose of/refine it appropriately.
A minimalistic computer input device that combines the function of a keyboard, mouse, joystick and -to some extent- a VR glove.
Knuckle Gears, Replacement for Universal Joints
A 5-moving-part gear assembly that can flex 360 degrees without shifting the phase of the shaft rotation.
Construction Toy Adaptor Set
Adaptors between different styles of construction toys
When I was a kid I was a big fan of construction toys, I had a Lego set, Tinkertoys and Toggle (now extinct) blocks, and my friends had Lincoln logs and Erector sets. Inevitably a kid with one construction set had more than one... So how can such a kid square his/her fun? Or even cube it? The Construction Toy Adaptor Set (CTAS)! Some CTAS kits are Lego blocks with Tinkertoy-gauge holes & pegs sprouting from the sides. Other kits contain Tinkertoy nodes with Lincoln log slots, or even Lego blocks with Erector set screw holes. Every new adaptor increases your building combinations geometrically... Pour all of your kid's construction toys into one can, 'cause now it's all one thing!
Interstar - slotty
toobers & zots
Eitech, Eitech Beginner
Zome - angular pegs and nodes with holes.
Supermag - magnetic