92 Gears is a lovely, hypnotic animated GIF. Ball Bearings in a Hypersphere is a mathematical discussion of its generalizations.
Justin Gershenson-Gates makes insects and spiders from mechanical watch parts. The Verge shows more pictures including one of a piece under construction, more photos are on Inhabitat, there are yet more photos at Twisted Sifter, and the artist has a personal website.
Intermeshing, rotating mechanical gears have been found in an insect. The gears act to ensure that the legs of the hopping insect move at the same rate when jumping, and are lost during molting to an adult stage. Via reddit, where the journalist is participating. Science magazine report (paywalled).
Ken Condal built an orrery (a mechanical model of the solar system - wikipedia), milling the parts himself using CNC machining. Among the videos are those of the orrery in operation and a time lapse of the construction process.
Mathematicians Henry Segerman and Saul Schleimer have produced a triple gear, three linked gears in space that can rotate together. A short writeup of the topology and geometry behind the triple gear on the arXiv.
Animated Engines has been mentioned a couple times before, but I wanted to highlight the site entire, along with its sister site, 507 Mechanical Movements. Both sites have animated diagrams of a huge variety of engines and (relatively) simple machines, the latter based on an 1868 book by Henry T. Brown of the same name. While all of the engines are animated, the animated machines start on page 3, and go on from there. And every diagram leads to a page that explains the machine's function — step-by-step in the case of the engines.
Television Without Pity re-capper Jacob Clifton has written a short steampunk story for Tor.com. “There’s a level on which the story is an indictment of using steampunk as a fashion or trend. It came about because I wanted to see what would happen if you substituted Jane Austen for Jules Verne in the steampunk equation...” The Commonplace Book
An article about the Free Universal Construction Kit -- for connecting Legos to Lincoln Logs to Tinker Toys to Fischertechnik to Duplos to Krinkles to Zometool to K'Nex to Zoob to gears. Designs at Thingiverse. A PDF page displaying all parts.
A perfect storm of terrible, two sharks trying to jump each other - Justin Bieber's steampunk version of 'Santa Claus is Coming to Town'.
Amazing, fun and interesting kinetic paper creations:Gear's heart [action starts at 0:49]. Paper Engineering by Kamikara. Some of his other creations in action: The Egg of the Dinosaur | Surprised Zombie | Globe Puzzle| Penguin Bomb | Mr. Grieve | His YouTube channel, girigiriou. Previously.
The kinetic sculptures of Anne Lilly.
There's weird taxidermy, weirder taxidermy, and weirdest taxidermy. There's even weird taxidermy auctions. But, all in all, these animals are the same old stuff. Lisa Black however has come up with a new spin on an old concept - steampunk taxidermy. Some images may be NSFW.
How a watch works in the clear, precise 1949 informational style.
Steve Durnin's D-Drive is a fascinating new infinitely-variable transmission that doesn't use friction components or a clutch of any kind. Video of a prototype with detailed explanations is included.
Back of the Mike | Around the Corner | Behind the Bright Lights | Sky Billboards | Just a Spark [more inside]
On a traditional steam locomotive the pistons drive the wheels directly via cranks. An unusual looking series of variants, the geared locomotives, took a different approach - using gears and driveshafts, giving them an advantage in traction at the cost of speed, making them ideal for steap grades and tight curves of logging railroads. The most common was the Shay Locomotive (video), with it's vertical pistons. Other variant included the Climax (video, seen at the Mount Rainier Scenic Railroad) and the Heisler, which had it's pistons in a V-formation (video). Many examples of the geared locomotive can be found at the Northwest Railway Museum.