Good design seems almost effortless, but great design is barely noticeable. Take the paper clip, Helvetica, or the “Greek” coffee cup that’s a staple of every corner deli. Designed in 1963 by Leslie Buck, a Czech immigrant and Sherri Cup Co. employee, the cup’s familiar Greek motif is both utterly banal and completely unforgettable.

That lowly cup pales in comparison to the high-tech aeronautics, military design, fashion, architecture, furniture, and animation in the third National Design Triennial, “Design Life Now,” which opens tomorrow at Cooper-Hewitt. Yet the same combination of inspiration and practicality that’s made Buck’s design ubiquitous applies to everything in the show, from iPods to dish racks.

The museum’s third survey of the best contemporary design in America, “Design Life Now” spans three floors and features the work of 87 designers and firms, including agencies and NGOs like NASA and Architecture for Humanity; corporations like Google, Apple, and Nike, and star architects like Santiago Calatrava and Rem Koolhaas, as well as emerging fashion and product designers.

The survey was organized by museum curators Barbara Bloemink, Ellen Lupton, and Matilda McQuaid, and guest curator Brooke Hodge, along with nominations collected from the public through a blog-style Web site.

The works on view range from concept to product, with schematics for bold experimental projects and buildings alongside new designs and media across a wide range of disciplines. But interdisciplinary approaches and socially conscious design are a common thread. If the Triennial has anything to say about the last three years — which in contemporary design is like a decade — it’s that crossing boundaries and reconciling opposites are the dominant themes.

So are hints of troubled times, as whimsy gives way to patently unironic practicality. The most blatant example combines civil defense with cutting-edge technology: a disconcerting virtual character named Sergeant John Blackwell, developed for military exercises by the Institute for Creative Technologies. Part of the Marina Del Rey company’s series of “leadership development tools,” Sergeant Blackwell can track movement and answer questions, as well as display different emotional states.

Post-Traumatic Stress Disorder isn’t one of them, but it is the focus of one of Hunter Hoffman’s virtual-reality environments. Besides developing immersive therapeutic scenarios for Iraq-war veterans, Mr. Hoffman has also designed SnowWorld, a VR “game” for severe burn victims. The interface features a snow-covered canyon populated by penguins and snowmen, which the viewer slams with snowballs to the music of Paul Simon. Mr. Simon is an enthusiastic supporter of the program, which can reduce between 50% and 90% of pain-related brain activity.

Along with applied design, the Triennial also focuses on design informed by biology and the natural world. Most prevalent is “biomimicry,” a reverse form of engineering where natural forms are used to solve complex design problems — now applied to everything from forks to artificial intelligence. Nike’s new running shoes emulate the physiognomic character of barefoot running, while Joseph Ayer’s sublime “Robolobster” replicates the body of its real counterpart in order to locate underwater mines.

The ultimate application of this sensibility is also the most stunning: robotics. Along with NASA’s Mars-trekking rovers, there’s David Hanson’s astonishing Albert Einstein — made using his patented polymer skin called Frubber — which can mimic human expression with amazing subtlety and answer questions to boot. Mr. Hanson hopes such technology can help people with communicative disorders.

The same technology is employed in consumer-toy designs and games throughout the exhibition. Wowwee Ltd. makes robot pets that respond to commands and perform tricks. Natalie Jeremijenko reprograms commercially made toy robots, including her pollution-sniffing dogs — an appropriation of technology that directly addresses the effects of high-tech manufacturing. Games like Will Wright’s popular “Sims” series turn this artificial intelligence into what’s known in the business as “God games.”

The Triennial also has its fair share of well-designed furniture, most notably Ransmeier & Floyd’s poetic, almost childlike dish rack. The renowned furniture company Herman Miller Inc. showcases new office furniture that breaks with the uninspiring monotony of the cubicle through interaction-based designs. Emeco, in the business since 1944, presents lightweight, utilitarian chair designs by Sir Norman Foster and Frank Gehry. And New Yorkers will appreciate Christopher Douglas’s multiuse, collapsible dining tables, chairs, benches, and coffee tables.

Some of the best work comes from the sustainable, DIY camp, where mass-market products and low-tech design practice go hand in hand. Mixing craft and technology, publications like the magazines Readymade and Make teach readers how to build, hack, and tinker with furniture and gadgets in ingeniously cheap ways. Projects that emphasize accessibility include Readymade’s CD racks made out of FedEx tubes, and Make’s brilliant aerial photography kit made from a kite and popsicle sticks.

The most remarkable form of this sensibility comes in the renewed surge in affordable and adaptable prefabricated housing and furniture, such as Lazor Office’s Flatpak flexible kit-ofparts house, and Konyk’s structurally brilliant designs. But it also extends to an emphasis on handwork in knitwear by Tom Scott, handmade jewelry by Judy Geib and Steven and William Ladd, and the painstakingly constructed fashion designs of Ralph Rucci, whose work will be celebrated in a retrospective at the Museum at FIT in January.

Design’s global giants are also prominently featured. Apple trots out the 5-year old iPod, certainly one of the biggest successes of the decade, while Google flaunts its world domination with a digital rendering of the world’s search usage, and a wall display of its hegemonic product line. (Is the company’s unofficial motto still “Don’t Be Evil”?)

But the Triennial’s real merit lies in celebrating the practical, client-based design that often goes overlooked outside the design world. Chip Kidd’s covers for titles by Jay McInerney and Augusten Burroughs, imaginative visual interpretations so intimately linked with the stories inside, are a case in point. These, like much of the work in the show, prove that great design isn’t just something to buy, but things that people can put to work, or that seem as perfectly simple as that blue-and-white coffee cup.

Tomorrow until July 29 (2 E.91st St. at Fifth Avenue, 212-849-8400).