It's always a bit awkward when the face that goes with the voice makes a public appearance. Ira Glass has been told he looks younger than his listeners thought, or older, or shorter, or not as fat. What amuses him most, though, is how often he gets told that he has a "great radio voice."

"One of the things that's weird if you've been on the air for 10 years is that everything seems inevitable to your audience -- like my performance," says Glass, host of the popular public radio show "This American Life."

"People think I have a great radio voice. I don't have a great radio voice. Men who have smoked have great radio voices, like Bob Edwards and Robert Siegel. Me, I have a voice that sounds exactly like everybody you know. It's just through sheer repetition that it starts to sound like it should be on the radio."

And the looks thing? Well, think about the voice. Seems a little nasally. A little nerdy. Kind of young. What image does that summon?

"If you stopped to think about it, it's exactly what you should guess," Glass, 46, says. "A glasses-wearing Jew."

Who are we to argue with that? When Glass appeared onstage last night at George Washington University's Lisner Auditorium, he was wearing oversize glasses with thick, black frames, a pinstripe suit and paisley tie, and his overall demeanor seemed to say, "Hip nerd." He joked in advance that he planned to give his usual stump speech ("A plan for economic revival. How I'm going to get us out of Iraq. Gratuitous swipes at the FCC," he volunteered by phone earlier in the week.) Actually, Glass's performance is a lot like his radio show, full of unique stories and narrative appeal.

He opened in pitch blackness ("this is radio, after all") to capture the power of words without visuals. Once the lights came up, he deadpanned: "Wow, you look nothing like what I expected!"

What followed were snippets of some of his best shows, and -- more to the point -- his explanations as to the story behind the story, his quest to "create stories that are packed with pleasurable surprises." Such as the woman who, after the Exxon Valdez oil spill, spent an inordinate amount of time explaining why Dove dishwashing liquid -- and only Dove -- should be used to clean affected birds. Or the supply soldier fixated on the candy-eating habits of the guys in her unit. (And, no, he didn't solve the nation's economic problems or present an Iraq pull-out plan. But he did get in a swipe at the FCC: "It would shock you, the logic behind these decisions," he said, then let loose a brief tirade.) He had his audience in stitches, which would come as no surprise to the 1.6 million listeners who tune in to 500 public radio stations every week to listen to Glass and his team take their audience on an intimate, funny exploration of some aspect of American life, whether it be what it feels like to be a 19-year-old Navy midshipman on an aircraft carrier or why a man still so loves a bull that has gored him. Or what happens, over 24 hours, in the lives of the people who populate a Chicago diner.

"This American Life" has its own structure, and sound, that distinguishes it from newsmagazine and other radio broadcasts. Shows are produced in acts. "We try to tell narratives," Glass says. "There are characters and situations and things unfold and people learn things. Or at least they have some thoughts about the experience."

Glass is a well-known perfectionist, and thus, says longtime producer Julie Snyder, so is the staff. "We anticipate Ira's perfectionism. The show is incredibly tightly produced to the point where when my husband hears the show, and he goes to make a comment, and he misses maybe 15 seconds, and it just breaks my heart that he missed that."

But it started to feel stale to just about everyone around the fifth or sixth year. "At that point," he says, "all of us who worked on the show really felt like we invented this format together, but that maybe we were a show like 'Seinfeld' -- a nice idea, but it plays itself out and you exhaust your format and everybody has to quit and do something else with their lives, like make American Express commercials."

Then 9/11 happened, and the Afghan and Iraq wars, and the public's appetite for news changed with it. It also energized the staff. Episodes were produced more quickly. Glass went out on that aircraft carrier with the soldiers. Reporters went into Iraq. More recently, "This American Life" did three episodes tied to Hurricane Katrina, which were noteworthy for what all the spectacular television and photographic coverage didn't always capture: the voices of the victims, unhurriedly explaining what had happened to their lives. "We got huge audience response from that," Glass says. "I think you really learn something when you listen to people talk at length."

The show started 10 years ago, when the Corporation for Public Broadcasting gave Chicago Public Radio money to start a show with the understanding that it would feature a broadcaster who had a national background. At the time, Glass had grown from being what "All Things Considered" co-anchor Siegel jokingly refers to as "one of the illegals" at NPR (helping research, cut and produce shows, but not technically on the books) to being the network's Chicago-based reporter. Glass agreed to sign on, and "This American Life" was born.

Well, technically, "Your Radio Playhouse" was born, but nobody much liked that name. Someone suggested to Glass that it be called "Glass House." He jokingly retorted that perhaps "Glass Hole" would be more apt. In the end, the staff seized upon a sign-off line ("we'll be back next week with more stories of this American life") and turned it into the name.

By the end of the first year, the show had been signed by 112 stations, and it rapidly became one of those rare public radio icons: a show all the stations want. And Glass found himself described in the same company as Garrison Keillor of "Prairie Home Companion" fame and NPR's Terry Gross ("Fresh Air").

There's even talk -- and much worry among public radio purists -- about turning Glass into a television star. He has shot a pilot version of the radio show for Showtime and is waiting to hear from the cable network whether it will be picked up.

"He is a cult hero in public radio," says Siegel. "He's a rock star."

Siegel hasn't seen the pilot, but he admits to having reservations.

"I just think that Ira and radio are too perfect a fit to be applied to television very effectively. But I'd be happy to be proved wrong."

Glass, for his part, is happy to have the new challenge -- as long as there aren't too many shots of him in the program and he doesn't have to get all obsessed about his wardrobe. And as long as the television show stays true to its radio roots.

"The show, as much as anything else, just exists as something to amuse us," Glass says. "Basically, it's to our taste. We're making stuff that we think is interesting, and we just assume that we're ordinary enough that other people will, too."

It's a pretty good description, but Glass was even more amused by the one he caught on Fox TV's steamy teen drama "The O.C." He has a soft spot for the whole teen-angst genre, and apparently the show's writers have a soft spot for him. Just this past week, he was flabbergasted to hear the show invoke "This American Life." And even vastly more amused to hear how teenage hottie Summer described his baby: "Oh, is that that show where all those hipster know-it-alls talk about how fascinating ordinary people are?"

Then she smirked.

Glass just stood up and pointed at his television in shock. Pleased shock, of course. Because he is just hip enough -- and just nerdy enough -- to know when he has hit a pop culture home run.

At a live show at GWU last night, Ira Glass, host of "This American Life," opened in pitch blackness to capture the power of words without visuals.