If you've never heard of Joi, don't fret. Hailing from Atlanta, she's a wild rock/soul diva who's never scored a major hit -- but she's been an underground darling for years. (She was even briefly a member of the soul trio Lucy Pearl.) Wanna know more about this mysterious lady who channels equal parts Janis Joplin and Heather Hunter? Well, she brings her sexually charged stage presence and off-the-wall catalog of original tunes to Charlotte tonight. Buy a ticket and get an education about this enigmatic talent. 21-and-over crowd. 9 p.m. $15. Tempo, 4809 Wilkinson Blvd. 704-391-8909. www.tempocharlotte.com.