What do Carlo Foust, medical technologist in the General Laboratory at Christiana Hospital, and Roy Halladay, Phillies pitching ace, have in common? They each have hurled perfect games this year. Foust bowled his second perfect 300 on Sept. 21 for the Christiana Care bowling league. He has led the league in high average for four straight. His magic night included games of 248, 238, and 300, for a series total of 786. For the last frame of his perfect game, the bowling alley was in total silence, with bowlers from all the other leagues watching.