Acrobatic moves in New York clubs earned Mark Alexander Knox the nickname Flex long before television did the rest. Discovered by DJ Spinderella, the Harlem native toured three years with Salt-N-Pepa's dance troupe and choreographed for Mary J. Blige and Queen Latifah, then turned to stand-up in 1989 and made his film debut in Juice (1992). After the acclaimed but short-lived sitcom Where I Live (…
