MURRAY — The 500 extension cords, the 100,000 lights, the 57 flying metal reindeer, the neon nativity scene, the bubble machine, his very own FM transmitter so he can synchronize all this to "Boogie Woogie Santa Claus" — it's tempting to conclude that Marty Slack is a fanatic. But as he told a reporter for CBS News last December: "I think I'm beyond fanatic. I was fanatic a few years ago."

Slack has become a Christmas icon in the Salt Lake Valley, where on a typical weekend night in mid-December a thousand cars snake through his neighborhood to get a look at his house at 5631 Whispering Pine Circle. And then last year his fame went global when he won grand prize in the PlanetChristmas Worldwide Decorating Contest. That was in the "over the top" category, in a contest where nearly everyone had multiple inflatable snowmen and programmable lights.

There were thousands of entries from all over the world, says PlanetChristmas founder Chuck Smith of Franklin, Tenn., who decided not to run a 2007 contest because "the people who lost took it very seriously."

There is no succinct term for people whose hobby is decorating their houses with Christmas lights. Smith has settled, instead, on the word "addict." In the chatroom on his Web site, he says, 6,000 people talk about Christmas 12 months a year.

If there is a typical Christmas lights addict, Smith says, it's a middle-aged man with extra money to spend and a vivid childhood memory of the one house in his neighborhood that went overboard with decorations.

Marty Slack can still remember the thrill of looking at Christmas lights from the back seat of his parents' car, and 40 years later he wants to re-create that feeling of enchantment, for himself and everybody else. He is fond of saying that he has often observed tired, ornery people drive up to his house — he imagines them, just minutes before, grumpily trudging through the mall — and then they see his display and suddenly they're smiling.

Slack's journey began in the early 1990s, the Christmas after he and his wife, Micalle, moved to their split-level. Micalle wanted some Christmas lights, so Marty hung a few strands along the rain gutter — which he left up till the next Christmas. By then the sun had bleached the reds and greens to white.

And then one thing led to another, he says. One year he built a 40-foot tower of lights, and another year a giant star. He was starting to get his Christmas excitement back. Pretty soon people were stopping to admire his work, which made him want to try even harder. So he added live music in his garage, and in 2003 he figured out how to do a synchronized light show.

Because Slack's creations can be viewed on his Web site, christmasutah.com, he gets letters and e-mail from all over the world. Some want tips for their own decorating. The ones who have seen the house in person thank him for cheering them up. One woman, who had lost both her husband and a son that year, credited Slack's extravagant, playful display with making her want to keep on living.