Off Broadstreet Theatre presents its latest musical comedy revue, “Accidentally Famous,” which opens Friday. After the failure of their TV reality show, “The Real Exes of Culver City,” four former wives and lovers of the same music producer, known only “accidentally” through tabloid coverage of their lives, have formed an “inspirational” singing group called Accidentally Famous. Realizing that success will only come from working together for the common good, the women “re-package” their experiences into a multi-faceted self-improvement program, which includes their CD, an exercise video, a calendar and their book, “Selling Your Book,” according to its author, Off Broadstreet …