I came across a magazine ad for a show on PBS called African American Lives. I did a double take and read it twice before realizing that it didn't mean what it was saying.
African American lives: African American is a noun and lives is a verb, as in he/she lives
African-American lives: African-American is an adjective and lives is a noun, as in happy lives
See, aren't hyphens great? I love the little suckers!