Despite what the name implies, the Hot Club of Cowtown is not Sacramento's hottest music venue. In fact, it's a jazz-influenced, Western Swing trio that formed in New York City's East Village. Thursday night, the band will be performing for the first time in Sacramento at the 24th Street Theatre. The Poplollys, a local hillbilly country band, and Hard Clumpin' Litter, a local blues band, will open the show. The Hot Club of Cowtown formed in 1998 when fiddle player Elana James responded to a Village Voice newspaper ad placed by guitarist Whit Smith. Upright bass player Bill Horton rounded out the trio, but was subsequently replaced by Jake Erwin. James was born to a violinist mother and