CREATE TABLE table_16242 ("No. in series" FLOAT, "No. in season" FLOAT, "Title" TEXT, "Directed by" TEXT, "Written by" TEXT, "Featured character ( s ) " TEXT, "Original air date" TEXT, "U.S. viewers  ( million ) " TEXT)

What is the title when original air date is may15,2008?
SELECT "Title" FROM table_16242 WHERE "Original air date" = 'May15,2008'
SELECT "Title" FROM "table_16242" WHERE "Original air date" = 'May15,2008'