Combine crackers, butter, and sugar, and pat into a buttered 9 inch pie pan. Beat cream cheese in large bowl, and add eggs, sugar, and beat until smooth. Pour into crumb shell. Bake at 350 degrees for 20 minutes. cool on a wire rack for 15 minutes. Combine sour cream, sugar, and vanilla, and spread over pie, then bake at 475 degrees for 5 minutes. Cool on rack, then refrigerate.