Puppet designer Rick Lyon, left, with Nicky, and John Tartaglia, with Rod, are the two original "Avenue Q" cast members who came to Las Vegas to open the second production of the hit musical. What began as a proposed TV sendup of "Sesame Street" evolved into a Tony-winning musical with more heart than people might expect.

There comes a day when a lucky person finds the job for which he is uniquely qualified. For John Tartaglia, it was "Avenue Q."

Tartaglia spent more than five years as an off-camera puppeteer for "Sesame Street," but "never thought I'd earn a Tony nomination with a puppet on my hand."

Most of those drawn to puppetry, he explains, enjoy the anonymity that enables one to perform, yet still hide. The hit musical "Avenue Q" is the rare gig that lets him be both a human and puppet operator. "I love to be onstage myself. That's more organic to me than anything else."

As part of the team that steered "Avenue Q" from a proposed TV satire of "Sesame Street" to Broadway hit, Tartaglia figures he is still in the minority of those not confused by its premise.

"I think people's first reactions might be that of, 'Huh?' '' he says.

Even today, after the three Tony Awards and all the publicity about an exclusive Wynn Las Vegas run pre-empting a national tour, director Jason Moore figures "Avenue Q" will be "a show that builds on word of mouth." As in New York, "we have to kind of let it sit around awhile."

The high-concept shorthand is that "Q," which opens for previews on Saturday, transports the young lost generation of "Rent" (from the same producers, no less) into an edgy satire of children's television. The place where the air is sweet is now, the script explains, a "dilapidated street in an outer, outer borough of New York City." But it's the only place where newcomer Princeton (Tartaglia in most performances) can afford to live as he asks himself, "What Do You Do with a B.A. in English?"

It's only three songs before Kate Monster, a kindergarten teaching assistant who happens to look very much like a Muppet, lets rip with the F-word in "It Sucks to Be Me." Other characters include a closeted gay Republican and the Internet-obsessed Trekkie Monster.

And Gary Coleman is the building superintendant. Not the actor, but another actor playing the grown-up child actor.

And yet, the end product is more sweet than savage. As Moore notes, "Sometimes what is quick to explain like that doesn't include what I think is the most valuable about it, which is this kind of heart that people talk about."

"There has to be an emotional investment," Tartaglia agrees. "You're a lot more moved than you expect to be. ... People are surprised when they're really feeling sorry for Kate Monster at the end of Act One."

The project jumped from the level of Second City-style sketch comedy when it came to the attention of "Rent" producers Jeffrey Seller and Kevin McCollum.

When he witnessed a workshop version, Seller says he laughed more than he had in a long time and realized "they're expressing something I know in a way I've never experienced before."

The producers were eager to deliver a follow-up to the nontraditional theater audiences they had created with "Rent." They steered the project from a proposed TV pitch into the hands of theater professionals such as Moore and writer Jeff Whitty.

From the first low-tech reading, "the one thing that got the most attention was people saying, 'We just loved watching the puppeteers work,' '' Tartaglia recalls. Soon it was decided that the actors would visibly operate the puppets. Still, Moore says "what eventually works about this show is we're just following characters. The fact that they're puppets becomes secondary after awhile."

The long-form musical opened off-Broadway in March 2003 and jumped to Broadway that summer. By the time the musical pulled its surprise coup at the June 2004 Tony Awards, the producers already had cut a deal with casino developer Steve Wynn.

Wynn approached the producers at a time when they were wary of some 3,000-seat theaters being forced on them for a national tour. "The primary concern for us was, 'How are we going to serve the play?' '' Seller recalls.

For his part, Wynn says, "the reason I went after 'Avenue Q' was because it was so counterculture to the Las Vegas tradition. I wanted that difference to be in my building. And I certainly hope that everyone enjoys it as much as I did. We'll see."

McCollum and Seller didn't walk into Las Vegas blind. They spent 11 months in 2000 and 2001 trying to launch De La Guarda, an avant-garde aerial troupe at the Rio. "Back then, we were actually trying to change the way in which people experienced theater," Seller says of the standing-room-only warehouse production.

By contrast, he calls "Avenue Q" "a fantastic conventional musical" with a tone that is "absolutely appropriate for Las Vegas."

Still, the announcement raised eyebrows from those who wonder how "The Internet is for Porn" will play on a Strip where, as Wynn notes, wit has not been a prized commodity.

Director Moore says: "I think that's sort of what remains to be seen. What does it mean if we move a Broadway show intact, with all the same intentions and all the same values we would ask for on Broadway? I think that's part of the experiment here."

For now, at least, Tartaglia and puppet designer Rick Lyon enjoy the kind of job security even a B.A. in English can't buy. "When we had to recast the show, we realized there aren't that many people who can do it," Tartaglia says of the puppetry.

"We had to kind of look to the acting world and find stage actors with no puppetry experience and teach them. They're trying to master an art that takes years and years to learn."