Interactive exhibits are nothing new. And George Fifield, guest curator of Milwaukee Art Museum's "Act/React" show, which opens today -- would be the first to admit that. But, he says, that's not what "Act/React" is, exactly.

"The only interface is your own body; your own intuitive knowledge of how to move through space," says Fifield, a Milwaukee native and founding director of Boston Cyberarts, Inc.

Unlike in most interactive shows, there is no computer mouse, there is nothing for the viewer to do with these installation pieces beyond simply being there and moving through the space. This means that thanks to its lack of interface, "Act/React" -- which is on view through Jan. 11, 2009 -- is the world's first unmediated interactive exhibition.

"You don't have to know how to manipulate the technology," Fifield says. It's not about the technology at all. It's about magic and metaphor."

"Explore," adds Fifield, "that's the operative word with this exhibition."

The show has 10 works by six artists from around the U.S. and Canada arrayed in the Baker/Rowland Galleries that host all of MAM's major exhibitions.

Entering the space, visitors find two works by Scott Snibbe. "Boundary Functions" is a retroreflective floor and when viewers step on to it, the floor automatically defines their personal space. Add more viewers and more spaces open up and the existing spaces change shape. Move around the floor and your space moves with you.

Across the room, there is "Deep Walls," with 16 video screens and a video camera. As a viewer steps into the camera's field, his movements are added to the rotating images on the screens. When the 17th person (or group of people) enters the camera's space, the first image is replaced, and so on, creating an ever changing catalog of your movements and those of your fellow viewers.

New Yorker Liz Phillips created "Echo Evolution," a room with neon lights and a synthesizer that are controlled by the number of people in the dark room, their movements, their lack of movement and their place in the space. Phillips told me she uses the same sensors that Polaroid cameras used to auto focus to track viewers. Those sensors send their information to the synthesizer and lights via a computer.

And Phillips, like other artists represented in "Act/React" sort of gets to the heart of the spirit of the exhibition when she admits that she -- like those of us coming to see the works -- is still learning about her own installation -- about its pitfalls, its strengths, what makes it tick.

"I feel sometimes like I have a misbehaving child," she jokes.

Other highlights are Daniel Rozin's "Peg Mirror," which stands out as something of an "organic" work. It is a circle comprising a series of wooden pegs that twirl to create a mirror image of the viewer. It is perhaps the exhibit's most surprising work.

At the end of the exhibition in a large space are three works by Camille Utterback. "External Measures," "Untitled 4" and "Untitled 6" each make use of a video camera, a projector and a computer to allow viewers to stand before each of these "paintings" and manipulate them with movement.

Utterback says she hopes that her beginnings as a painter are clear in these works and she can rest easily as they are the most obviously "painterly" works in "Act/React."

The show is astonishing, really, and if you've been waiting for a reason to bring your kids back to the art museum (although, let's face it, there's something for them there every single day of the year), this is the perfect opportunity as young minds will be challenged, engaged and wowed by these works.

For Fifield, the show is a dream come true.

"In many ways this is my dream exhibition," he says. "And to be able to bring it to the town where I grew up is a real treat for me. I'm very excited."

And so are we.