MUSIC: As we already mentioned, Why? is performing this evening along with Dose One, Cryptacize, DJ Odd Nosdam, DJ Jel. 8 p.m. // Great American Music Hall [859 O'Farrell] // $13 *THEATER: Eve Ensler's Obie Award-winning play the Vagina Monologues -- featuring such monologues as I Was Twelve, My Mother Slapped Me, My Angry Vagina, My Vagina Was My Village, The Little Coochie Snorcher, and more -- takes the stage in the Castro for......