Colorado's Yonder Mountain String Band liberated themselves from the traditional style of acoustic bluegrass music long ago, their sound retaining its rootsy mountain flavor while incorporating elements of funk, rock, hip-hop and any other genre that tickles their fancy. The foursome has attracted a steadily growing fanbase with spirited live shows featuring plenty of freewheeling improvisation, fast-pickin' prowess and soaring four-part harmonies. Their fourth studio album and self-titled debut on Vanguard Records saw them furthering their musical explorations with help from rock producer Tom Rothrock (Foo Fighters, Beck), and under his leadership, the group developed a more spontaneous approach to its songwriting and incorporated drums into the banjo/bass/mandolin/guitar mix. Yonder Mountain String Band stops in St. Petersburg this weekend as part of their 2007 Cabin Fever Tour. Sat., Feb. 10, 8 p.m., Jannus Landing, 16 Second St. N., St. Petersburg, $20 in advance/$20 day of show, 727-895-3045, jannuslandingconcerts.com.