BANGOR — Alisa Henry, 10, launched herself into a midair somersault and then landed upside down on a sticky Velcro wall.

The Fairmount School pupil remained inverted for a few moments, contemplating the huge crowd mulling nearby, until a kindly adult righted her.

For Alisa, the Velcro venture was well worth the 35-minute wait in line to get her turn. Seeing the world from an upside down angle was “great, weird. I want to do it again,” she added.

The action-packed display was a key attraction Thursday at the event in downtown Bangor to promote the fledgling Eastern Maine Children’s Museum.

A puppet show, live music, face painting and an opportunity to “Make your own Gak” — a claylike concoction — were highlights of a celebration that drew hundreds to the former Freese’s building on Main Street.

Many simply wanted a peek at the future home of the museum, scheduled to open in December 2000. Others focused on the trays of free food and free T-shirts offered at the event. Supplies of both completely disappeared within the first half-hour.

About 2,500 people attended the event, which lasted from noon to 3 p.m.

Some families with small children walked in one door and out the nearest exit, apparently disappointed and a bit fearful for their toddlers when they saw the jampacked rooms. A few others never made it inside, choosing to leave as soon as they spotted the long line waiting outside in nippy November weather.

Heavy promotion and strategic timing — the celebration began after the Veteran’s Day parade — made for a crowd that seemed to overwhelm event organizers, although they were cheered by the show of support, they said.

Throngs of parents and children walked shoulder-to-shoulder on the building’s first floor, while a long line of waiting visitors snaked up Main Street and onto adjoining Water Street.

The third such museum in the state, and the first to serve northern and Down East Maine, the Eastern Maine Children’s Museum will occupy three floors of the former Freese’s building on Main Street.

Plans call for the finished museum to feature an exotic array of educational displays and hands-on experiences for children 12 and younger.

The museum will give kids a chance to make their own hydro power on a river and to climb inside the replica of a beaver dam. They can climb to another floor of the museum inside a huge, lifelike replica of a tree trunk.

Youngsters also will be able to sample food and learn customs from other nations and explore the inner realm of the human body in age-appropriate activities.

The displays are being planned by professional architects and museum planners, but Thursday’s open house gave people few clues to the appearance of the museum when it opens its doors 13 months from now.

Makeshift displays were plunked on cement floors. Magicians and musicians worked amid a backdrop of plaster and renovations.

Despite the crowd, most people had smiles on their faces as they slowly wove through the first-floor area.

Bangor Mayor Michael Aube proclaimed the event a “wonderful example” of community suport for the museum concept.

“When was the last time you saw a long line at the Freese’s building?” asked Aube.

While event organizers stared in amazement at the crowd, they were cheered by the turnout.

“It’s amazing. I’m stunned, actually,” said Sean Faircloth, director of Partnerships for Healthy Communities, which led the grass-roots effort to get the museum on its way.

Support for a children’s museum in the Bangor area has been strong since the idea was launched in 1996, according to Susan Carlisle, head of the museum’s capital campaign.

Boosted by $900,000 from Stephen and Tabitha King, $250,000 from Jay and Hope Benton of Bangor and corporate contributions totaling more than $2 million, the museum has a solid funding base.

Carlisle, who attended the event, is heading the final phase of fund-raising for the project, which is seeking to raise $1.5 million in the next few months to assure a smooth financial start.

“I really think it’s a project whose time has come,” Carlisle said.