Improvisation is the lifeblood of dance. It's not seen all that often onstage, though, partly because it's a tough sell. "There's no safety net for the audience or the performer," says Dance Improvisation Festival curator Lisa Gonzales. In the works for three years, this weeklong festival naturally includes plenty of workshops and jams. But audiences will be able to ride the improv roller coaster at several shows, performed by national and local artists taking a whole range of approaches. Some participants have a concept in mind. Bebe Miller tackles "story-ness" in her untitled solo (Thu 6/16, 8 PM, Link's Hall, 3435 N. Sheffield), while Chris Aiken and Angie Hauser's Utopia Parkway is inspired by Joseph Cornell's boxes (Sat 6/18, 8 PM, Dance Center of Columbia College, 1306 S. Michigan) Other performers just jump off the cliff blindfolded. Collaborations . . . From Scratch features contact improv guru Nancy Stark Smith performing with pianist Mike Vargas, as well as Gonzales's troupe, the Architects, performing with free jazz group Ensemble V (Fri 6/17, 8 PM, Dance Center of Columbia College, 1306 S. Michigan). "The skill as an improviser is to be able to notice what's happening and to build the theater," Gonzales says. "We want to create something."