Lucky us!   Sexmob brings the virtuosic mayhem for a second time this month.  For those of you uninitiated, Sex Mob is a New York City jazz band, originally formed as a Knitting Factory vehicle for Steven Bernstein to exercise his slide trumpet.  They are truly beyond compare.  Check out this lineup:  Kenny Wollesen on drums.  Tony Scherr on bass.  Briggan Krauss on sax.   And the inimitable Steven Bernstein on slide trumpet.   Expect a high proportion of covers, usually familiar pop songs, given a humorous, but avant garde treatment. Bernstein points out that this is a return to a fundamental jazz tradition, to take a familiar song then disassemble and reassemble.