I'm a huge fan of Larry Niven's "Known Space" universe. Thanks to collaborations and the popular "Man-Kzin Wars" collections there are now hundreds of stories and over a dozen novels that take advantage of the setting. They vary wildly in quality, but even the lesser entries are usually entertaining, if not thought provoking. If nothing else, the creation of the Ringworld and the "Kzinti Lesson" ensures their place in science fiction's hall of fame.
Given my fanboyism, you can imagine how much I enjoyed discovering that someone was producing props drawn from the stories. As part of her Industrial Design classes, Lauren Gail Anderson has been making recreations of Niven's tasp, a Puppeteer disintegrator, and a Kzinti variable sword.
The tasp is a device that directly stimulates the pleasure centers of the brain. At first thought it's a wonderfully humane non-lethal weapon, but it's actually one of the most horrific technologies ever created. Anderson's prop is a handheld model, designed for human pranksters.
Her disintegrator rifle is the Puppeteer-manufactured model from "Ringworld". Which would actually make it an "excavator", since only Humans and Kzin see harmless tools as weapons. Heh.
Finally, she brings us one of my dream props- a variable sword. This is an oversized Kzinti model and features a light-up blade and marker ball. In the early stories the field reinforced monomolecular blade was invisible, hence the glowing red ball at the tip so the user didn't slice their own arm off. Later iterations used light to make the danger space of the blade visible.
If you head over to her blog she has a gallery of pictures capturing the design and build process for each item.