Morris, 36, is the most notorious choreographer on the contemporary scene. Many critics think he’s brilliant, a few emphatically disagree and legions of fans would follow him anywhere those long, luxurious curls beckoned. On his stage, gender roles are freely traded, and both sexes dance with an earthy, sometimes lumbering quality, as if their own agile bodies had taken on the weight of his hefty one. Morris is famous for a cut-the-crap attitude toward dance and life, and the closest he has ever come to family values in his choreography is a piece called “Lovey,” about child abuse. So why “Nutcracker”? “I’ve been told by people who were there that we were in a bar talking about Tchaikovsky,” he says. “I wanted to do one of the big Tchaikovsky numbers and somebody said ‘Nutcracker,’ and I said yeah, sure, OK. And then it came true.”

For the rest of us, “The Hard Nut” comes true this Wednesday, Dec. 16, when it will be broadcast on the PBS series “Great Performances.” Morris’s company is also performing “The Hard Nut” live this month at New York’s Brooklyn Academy of Music. The show is a riot, much of the time-fast and funny and wonderfully acted. Older kids will like it, but send the toddlers to bed. Those rats are scary. Like other artists who make classic works “relevant” by hauling them into the late 20th century, Morris says his chief aim was to be faithful to the original-in this case to the original 1816 German fairy tale “The Nutcracker and the Mouse King” by E.T.A. Hoffmann. When Marius Petipa and Lev Ivanov staged the first “Nutcracker” ballet-100 years ago in St. Petersburg-they sweetened the Hoffmann story considerably. Today, “Nutcracker” is still performed most often as a 19th-century Christmas confection, the stage brimming with exalted children. Not Morris’s version. “I don’t think children today recognize themselves in mincing, late-19th-century behavior and knee britches,” says Morris. “I’m not saying, pee-yew, I hate all ‘Nutcracker’s. That’s not true. I love Balanchine’s ‘Nutcracker.’ This isn’t a counter-‘Nutcracker’; it is ‘Nutcracker’.”

Nope, it isn’t. It is Mark Morris. And often, it’s Morris at his best. His version sticks to the Tchaikovsky music, but it’s set in a cartoon-style 1960s and peopled with brazen misfits. Portly Mrs. Stahlbaum, who overshadows her timid husband, drinks too much; their elder daughter, Louise, is a teenage vamp; their little son Fritz is a monster who hurtles himself around like a rubber band shot from a stick, and the heroine, young Marie, wanders in a state of perpetual bedazzlement. (All the children’s parts are played by adults.) In the first-act party scene, where ranks of children traditionally display social dances of great decorum, a bunch of ill-mannered guests do the bump and the stroll-promenading down the center of the stage with bad grace in a hilarious nod to Balanchine’s elegant tots. Morris is the guy in the Afro and bell-bottoms, the one who makes a boozy peace sign when they all gather around a guitar to sing folk songs. As always, the mysterious guest Drosselmeyer shows up with a nutcracker, which comes to life and, with Marie’s help, battles an army of rats. But the snow scene that follows is a lot flakier than most: men and women, all in white tutus, rush onstage throwing handfuls of snow in the air. This isn’t very credible as ballet but several dancers are on point, with gender no object.

Instead of sending Marie and the nutcracker (now a princely youth) off to the land of sweets, Morris changes tracks entirely in the second act. Here he draws on a creepy subplot in the Hoffmann tale, about a fierce Rat Queen who bites the baby princess Pirlipat and turns her into an ugly freak. Only the magical Hard Nut can break the spell, so Drosselmeyer goes in search of it. On his travels, he encounters novel versions of most of the national dances traditional to this act, including a wonderful Spanish duet for matador and lady bull and a French number for a quartet of dainty fashion plates, one carrying a baguette. All ends happily with a unisex “Waltz of the Flowers” and a romantic pas de deux for Marie and the youth. Actually, it’s a pas de deux for everyone. Flowers, party guests, fashion plates-the whole cast participates, one or two at a time lifting Marie or her swain, and everyone sweeping across the stage with joy.

“The Hard Nut” makes a fine playing field for Morris’s wit and his ardent theatricality. What flattens the fun in this production is his choreography. The gender free-for-all, for instance, works beautifully as a character device: Mrs. Stahlbaum (Peter Wing Healey) and the maid (Kraig Patterson) are among the most fully realized comic figures anywhere in modern dance. They’re not just female impersonations; they’re real works of the imagination. But when the men don tutus and go skipping around in Morris’s characteristically bland style, everything goes gray and mushy. It’s as if a giant eraser has passed over the stage and wiped out the brightest signs of life. His dance vocabulary is too limited and his musicality too literal to keep the magic going. Even in the finale, the strength of the image comes more from Morris’s idea than his steps. It’s entrancing to see the whole group support the couple; how much more so it would be if anyone were actually moving in an arresting fashion. In the end, “The Hard Nut” makes a great show but not a great “Nutcracker.” The great “Nutcracker"s are more than spectacles; they’re ballets, and their subject is music. Morris is true to long-forgotten bits of the Hoffmann story, but he’s missed the most important story of all-the one told by Tchaikovsky. It’s all about dancing.