Neyla Pekarek, a cellist, singer and former member of the Lumineers, has long been fascinated by Kate Slaughterback, who gained fame in the 1920s for killing 140 rattlesnakes that were attempting to slither toward her, her son and her horse on their homestead in northern Colorado; she made a flapper dress of the snakes' skins that is now a Greeley museum artifact. This year, the Denver Center for the Performing Arts presented a much larger memorial to this colorful pioneer: a full production of the musical Rattlesnake Kate, based on Pekarek's concept, scored by Pekarek, and written by playwright Karen Hartman.