In its 100-year existence Paris' majestic Grand Palais Museum has never hosted anything like it -- a battery of barmy Heath Robinson contraptions that clang, creak, explode and generally make people laugh.
Most museum goers spend an hour or two at an exhibition. At the Grand Repertoire they stay entire afternoons, entranced by a world where pigs really do fly.
"Ladies and gentlemen," announces Mitch, an actor and contraption designer from Marseille. "The Hale Bopp comet."
"This comet is mounted on a 1950s British BSA motorbike. It has an 18-horse-power engine. I counted the horses this morning," he says.
He straddles the spluttering engine, revs hard and the comet shoots 12m up into the air. The audience gasps.
"I've been five years old again for the past two hours," smiles 41-year-old spectator Marie, brushing flecks of soapy snow out of her hair.
"Ah yes, the snow machine," recalls Jacky, another actor-cum-mechanical wizard, struggling out of a battery-powered skirt that whirls like a dervish while he stands still.
"We used it for a scene in The True History of France 22 years ago. Now that was epic street theater. The scene featured Napoleon in a sulk retreating from Moscow in flames in the middle of a snow blizzard. It was a job to pull off," he says.
Although many deserve a category all of their own, the machines on display here loosely serve four different purposes.
First there are the "living" machines, giants and huge animals around which whole shows revolve. Royal de Luxe's 12m giraffe, with its beautifully sculpted face and graceful movements, appears more alive than the 25 Liliputian humans operating its 25 tonne frame.
Then there are "hidden" machines for producing effects -- rain, wind, ghosts and earthquakes.
One of Jacky's favorites is a lump of rusty piping that turns a noxious mix of explosives and diesel into 50m smoke rings.
"You hide it in a town and send up a huge smoke ring. The public chases after it. By the time they've got there, you've moved the machine and sent up another smoke ring somewhere else," he says.
Into the third group fall "theatrical" machines. These also produce special effects, using domestic objects like electric fans and egg whisks, but here the -- very visible -- process of production is as important as the end result.
Take the Rhinocerous Sound Machine, an assembly of traffic cones, train horns and other everyday objects. Playing them is an art, as fun to watch as it is to hear.
Perhaps the most enchanting group is of machines that are absurd, surreal, poetic and totally useless.
Many are contraptions for complicating life, like the Machine for Spreading Nutella on Bread, the Bicycle That Leaves Cow Hoofprints Behind It and the gloriously kitsch Masturbatorer.
By turns dramatic, whimsical or plain daft, they seek to engage the public's emotions and encourage them to view ordinary objects in a new light.