Officials with the Madison Children 's Museum explore their future home like children tackling a play project.

They unleash their imagination and fire up their creativity. Wending their way through a warren of small offices, they envision a spacious community concourse with a friendly cafe and parking for strollers.

Standing atop a steep stairway, they see young adventurers clambering across a suspension bridge into the early childhood area with its treehouse and huts.

Huddled under lowered ceilings in the 79-year-old building on Capitol Square, they dream of two-story windows that will flood the entrance with natural light as families pour in the front door from Capitol Square.

Museum officials will unveil their plans for a new museum at a news conference today at 10 a.m. at the future site of the museum, a renovated building at 100 N. Hamilton St. They will also discuss their progress on a $10 million fundraising drive aimed at opening museum doors by the summer of 2010.

Those doors will open to 41,570 square feet, a nearly five-fold increase from the museum 's current home at 100 State St. In the renovated building, which once housed a Montgomery Ward store and, later, state offices, the museum expects to welcome more than 82,000 visitors a year.

They 'll find on-site parking, a rooftop garden designed for year-round use, family bathrooms, creative play opportunities and space for the thousands fourth-graders who visit the Wisconsin Capitol each year.

In addition to welcoming curious children, the Madison Children 's Museum also intends to welcome visitors to Downtown, which can be confusing to families who don 't get to Capitol Square very often.

"I 'm excited that the museum will be more accessible to people who are intimidated by the Square, by parking, and by just coming down here, " said Jan DeAtley of Mount Horeb. She and her husband, Bill, have donated $1 million toward the new museum.

Launched with a $5 million site-purchasing gift from philanthropist W. Jerome Frautschi and the Overture Foundation, the $10 million "Ready, Set ... Grow! " campaign is past its halfway mark. A $500,000 donation is to be announced today from the Evjue Foundation.

Donations have topped $5.8 million so far, with nearly $2.9 million from foundations, $2.2 million from individuals and nearly $676,000 from corporations, museum officials said.

In pledging $20,000 for the project this month, Summit Credit Union said it especially respects the museum 's outreach effort for underprivileged children and their families.

Construction work is expected to begin later this year to renovate the building 's first two floors and rooftop. The project has been designed by The Kubala Washatko Architects of Cedarburg; the contractor is J.H. Findorff & Son of Madison.

As they imagine the new museum with its delights for little ones, museum officials paint a broader picture offered by children growing up to be problem-solving citizens and workers.

"We want to create kids who are ready to learn, " said Ruth Shelly, executive director. "The life skills that kids learn at an early age are an investment in the future. " That vision fuels about 300 children 's museums nationwide -- nine of them in Wisconsin -- and another 70 on their way to opening, according to the Association of Children 's Museums, a national group that honored the Madison museum in 1999 for its commitment to environmentally friendly design.

"Children 's museums serve as a kind of town square, where families of all backgrounds meet to play and learn about the world around them, " said Janet Rice Elman, executive director of the association.

A children 's museum is an economic asset in terms of quality of life, tourism and helping children prepare for knowledge-based jobs in a changing economy, said Rafael Carbonell, executive vice president of Thrive, a regional economic development organization for Dane and seven surrounding counties.

Eliot Butler, chairman of the museum board and president of The Great Dane Pub and Brewing Co., is looking ahead after years of planning, listening and squeezing 82,323 visitors a year into the crowded State Street museum.