"Mr. Rogers' Neighborhood" just got a bit bigger -- and a lot more fun.

Anyone who ever wanted to don a cardigan and sneakers, watch Picture Picture or take a trolley to the Neighborhood of Make-Believe now has a chance in an expanded exhibit honoring children's most trusted friend at the revamped Children's Museum of Pittsburgh.

The Mr. Rogers exhibit is a main attraction at the museum, which reopens Saturday after a two-month, $28 million expansion that quadrupled its size.

The museum, now more than 80,000 square feet, begs visitors to play -- from the articulated cloud, a screen that ripples in the wind above the new entrance, to interactive video installations that allow visitors to "catch" raining letters, to water exhibits that allow visitors to be a plumber or build boats and sail them through locks and dams.

"We think that a lot of learning comes from play. It is how a lot of children learn about the world, and all of us, too. We wanted to make the best play experiences that we could," Jane Werner, executive director of the museum, said. "My kids are 11 and 15 and they had a good time. They're a little jaded, they've been to a lot of museums, but they're engaged."

The expanded Neighborhood, which was only King Friday's castle in the Neighborhood of Make-Believe in the previous exhibit, is no different. From a television set hanging above the entrance, Rogers -- wearing his signature cardigan -- welcomes visitors to the Neighborhood and sets the tone for the exhibit, describing it as a place to "think about, talk about or play about all kinds of things."

Before entering, Mr. Rogers says it might be a good time to give whoever brought you to the museum a hug.

David Newell, who played Mr. McFeely on the show, said the exhibit embraces Rogers's idea of "permissible regression."

"It is okay from time to time to remember your childhood and remember what a good time you had," Newell said. "When we started brainstorming, Fred especially didn't want it to be behind glass. We wanted kids to be able to play. Fred always said that a child's play is their work."

Inside, there's a closet of cardigans and sneakers to let children -- and grown-ups within a certain size -- pretend to be Mr. Rogers. Also hanging in the closet is a blue cardigan Rogers wore on the show around 1970.

After that, visitors can play where or how they want. A replica of the trolley to the Neighborhood of Make-Believe sits in the middle of the exhibit, acting as a gateway from Mr. Rogers's house -- including Picture Picture and the fish tank -- to the neighborhood, complete with King Friday's castle.

Visitors can pretend to drive the life-size trolley or head to the trolley bench, where at the touch of a button the trolley will zip back and forth from tunnels in the wall leading to the Neighborhood of Make-Believe. They also have a chance to make and watch their own live version of the show using two closed-circuit television cameras.

The items from Rogers's house include the stoplight, a player piano and a television with cherished moments from "Mr. Rogers' Neighborhood," including a clip of Rogers buttoning a sweater wrong in 1973 (he switched to zippers around 1973) and struggling to sing and act out the song "Head, Shoulders, Knees and Toes" with musician Ella Jenkins in 1985.

In the Neighborhood of Make-Believe, visitors can put on their own puppet shows or dress up as royalty in King Friday's castle or play house in X the Owl's and Henrietta Pussycat's treehouse. A wall inside the castle has 26 rooms, one for each letter of the alphabet. Chirping crickets play when "N" for "Night noise" is opened, Prince Tuesday practices his piano (with mistakes) inside the "P" room, and inside "S" two people swing on a miniature swing set.

A trolley modeled on the one in "Mr. Rogers' Neighborhood" is part of an exhibit at Pittsburgh's newly expanded Children's Museum, which reopens Saturday. Jane Werner, executive director of the museum, shows how visitors can try on a cardigan sweater.