The cult mystery Jack's Back (1988) casts James Spader as twin brothers. One studies medicine, the other gets accused of murder on the one hundredth anniversary of England's notorious Jack the Ripper killings. The complex, trickily intertwined plot is executed most convincingly, with Spader pulling off his dual roles with impressive inventiveness. Cynthia Gibb spices up the intrigue with a delicious revelation of her undergarments. Jack's Back to make you whack.