Crayon Physics is lots of fun; you can draw objects that immediately behave like they would in the real world.
(Crayon physics video)
If you like, you can get the download from Kloonigames and try it out yourself.
When I thought about this, I immediately remembered Sketch Furniture Ultra Rapid Prototyping. A computer system watched you draw in space with your "magic crayon" and then immediately fabricated your drawing out of actual plastic.
Technovelgy (that's tech-novel-gee!)
is devoted to the creative science inventions and ideas of sf authors. Look for
the Invention Category that interests
you, the Glossary, the Invention
Timeline, or see what's New.
Illustrating Classic Heinlein With AI
'Stasis, cold sleep, hibernation, hypothermia, reduced metabolism, call it what you will - the logistics-medicine research teams had found a way to stack people like cordwood and use them when needed.'
Deflector Plasma Screen For Drones ala Star Wars
'If the enemy persists in attacking or even intensifies their power, the density of the plasma in space will suddenly increase, causing it to reflect most of the incoming energy like a mirror.'