Place 14 of the graham crackers in food processor and cover. Process until finely ground. Add butter and 1/4 cup of the sugar; mix well. Press onto bottom of 13x9-inch baking pan. Coarsely chop remaining 4 graham crackers and set aside.
Mix cream cheese, remaining sugar and vanilla with mixer until well blended. Add eggs and blend. Stir in half of the chopped candy. Pour into crust. Sprinkle with remaining candy, marshamallows and chopped graham crackers.
Bake at 350° for 40 minutes or until center is almost set. Cool. Refrigerate 3 hours or overnight. Cut into bars.