The Carolina Chocolate Drops are a band with a mission- to underline the connections between American bluegrass and folk with the genres' little-known ancestry in Africa. Though the project is high minded, their searing takes on instrumental and vocal standards are virtuosic, and their between-song banter is as witty as it is enlightening. Royce Hall, UCLA. 8 p.m. Fri. $20. uclalive.org.