Dripping with about equal parts nostalgia, playful lunacy and orangey-whitish gobs of delight, an American icon will continue its crawl from the underground back to the pop-culture melting pot this weekend.

We speak of the beloved grilled cheese sandwich, which will take center stage Saturday at the sixth annual Grilled Cheese Invitational, an inspired morsel of wackiness that has outgrown downtown Los Angeles lofts and moved uptown to Griffith Park.

Los Angeles-based comedy writer Tim Walker, the brainchild of this thing, explained its 2003 genesis thusly: "It was mainly because I was a fairly broke vegetarian at the time, and grilled cheese sandwiches came in handy."

Fellow starving artists suggested a competition.

"The first event was such an amazing success that the second one was an automatic," Walker said, adding that they were held in his artist's loft. "It's really touched a nerve it has a special connection with a lot of people."

The nostalgia factor casts high flames here. Most people's first grilled cheese sandwich, Walker noted, likely came from Mom, armed with Wonder bread and a stack of cheese singles. Many a poor college kid subsisted on such sandwiches and dubbed them "cheesers." They've been called the ultimate comfort food and, in combination with tomato soup, the all-American lunch.

But something hip's happened to this gooey, iconic symbol of more innocent times. Restaurants geared to them are springing up around the country. The folks at Kraft claim that grilled cheese is the second-most preferred non-deli sandwich nationwide. And grilled cheeses are breaking from the strict bread-butter-cheese mold.

"These days, a lot of people are going gourmet with them," Walker noted.

The Grilled Cheese Invitational adds to the changing cheese melange warmly. This kitsch-in-the-kitchen contest draws from a wide slice of life, everyone from professional chefs packing exotic ingredients to housewives using the time-honored combo of Wonder bread and cheese singles.

"And we've had both win," noted Walker, a 35-year-old writer-performer who's done pilots for the SciFi Channel and Spike Network.

Some of its rules and guidelines are serious, such as the definitions of bread, butter and cheese, judging criteria and equipment that's not allowed. Many of them are not, such as its insistence on calling all such concoctions "sammiches" and the suggestion that people have sex before competing to ease the event's tension.

Per usual, people who attend will judge the entries.

Sandwiches, er sammiches, are judged in four divisions. For purists, there's the "Missionary Position" category — standard white bread, orange cheese and butter. The "Spoons" category, new this year, opens it up to any kind of all three. The "Kama Sutra" category throws it full throttle to any kind of all three plus additional ingredients. Lastly, the "Honey Pot" is for sammiches with a sweet flavor that make them best served as a dessert. Yes, a dessert.

If an idle mind is the devil's workshop, imagine where that goes at a loosey-goosey event involving melted cheese.

For instance, there was the guy who brought his bread, butter and cheese — and dyed them all blue.

"None of it tasted like a grilled cheese sandwich," Walker advised, "but it was a sight to behold."

So was the grilled cheese sandwich built to resemble a castle, with little Legos around it as its defense fortress.

A woman made a grilled cheese sandwich in the form of a wedding cake, frosting the tiers with cans of EZ Cheese.

"Now that sounds shocking, but let me tell you there wasn't a morsel left on that plate," Walker said, marvel still in his voice as he recalled hunger's wanton destruction. "When it was done, a pack of wolves descended upon that thing and devoured it."

Walker thinks that it was about 3 feet high. The woman's blog stated it held more than 70 sandwiches.

Competitors have exotic names for their creations — The Leaning Tower of Cheese-a, Cheesus Christ, Molten Fury and Americanized Killer Bee Sammich were among last year's entries.

People, Walker reported, show up in cheese costumes. Last year, some contenders brought their own cheerleading squads. "People get really excited for the event," he said. "That's what's fun about it."

Walker's ideal grilled cheese sandwich? Olive loaf bread, Gruyere cheese, caramelized onions and "a nice organic Irish butter." No joke here; that actually does sound yummy.

Gruyere cheese originated in Switzerland. "It's a champion melter," Walker said with all the gusto of a track tipster touting a racehorse.

The event's good word of mouth has forced the move to Griffith Park, or as Walker put it, "This year we're going public. It has been an underground event."

Even so, the specific Griffith Park locale is being kept a secret. The only way people can get it is by subscribing to an e-mail announcement list on the home page of the event's Web site, http://www.grilledcheeseinvitational.com.

That, Walker said, is a mild stab at crowd control — not that he expects it'll stop determined aficionados.

"The word has gotten out and people want cheese, and they're going to get it one way or the other," he deadpanned.

Kraft Singles has come aboard as a sponsor this year. Normally, mere mention of the word corporate is anathema to such cultlike events, but Walker, for one, is grateful.

"In the past," he explained, "we've never had enough grilled cheese sandwiches. Kraft is in this year as the white knight. They'll be cranking out grilled cheeses until they are told to stop."

From 16 competitors and maybe 80 people attending the first year, Walker is expecting 100 to 150 entries and more than 1,000 observers this year.

Similar regional events have been held in Oakland and Austin, Texas. Just around the cheese wheel is an international event slated for Toronto in June or July. There's talk of expanding to other cities.

Walker is a bit concerned about what his baby has wrought but realizes he's helpless.

"Even if I didn't want the event to grow big," he said, "the power of cheese compels me to move it forward."