More challenges loom for Hizzoner Bloomberg's controversial bid to require third graders to pass reading and math tests before advancing to the next grade (see Gadfly, Volume 4, Number 7). Lawyers from the NAACP Legal Defense Fund this week posted notices to various education listservs, fishing for plaintiffs for a lawsuit challenging the practice. (Unfortunately, the notices are not to be found on the web.) "Who are the ideal plaintiffs?" reads the notice. "African-American, Latino, Asian, and white students who scored at Level 1 on one or both of the exams . . . and were not otherwise promoted through the appeals process" and come from troubled city school districts such as Ocean Hill-Brownsville and Bedford-Stuyvesant. The attorneys want students whose grades were good enough to pass on to fourth grade but were denied because of poor scores on reading and math tests. We suspect this case is a non-starter (the courts have consistently upheld testing for purposes of determining graduation or advancement to the next level), but if it gets off the ground it's one more headache for Bloomberg and schools chancellor Joel Klein.