The Extensible Processing of Queries (EPOQ) Query Optimizer
First described in Gail's PhD thesis, and a paper in VLDB'93. Preliminary design by Solveig Bjarnestad. Currently Misty Nodine, Mitch Cherniack and a cast of thousands (or at least 190). Plan Generation by Ted Leung. Execution Engine (POPS) by CS191 '93.