1. Preheat oven to 325°. Remove skin from ham, and trim fat to 1/4-inch thickness. Make shallow cuts in fat 1 inch apart in a diamond pattern. Place ham, fat side up, in a roasting pan; add ginger ale and bourbon to pan. Cover loosely with foil.
2. Bake, covered, at 325° for 4 to 4 1/2 hours or until a meat thermometer inserted into ham registers 140°, basting with pan juices every 30 minutes.
3. Stir together brown sugar and next 4 ingredients. Remove ham from oven; uncover and sprinkle sugar mixture over ham, lightly pressing mixture into fat.
4. Bake, uncovered, at 325° for 20 to 25 minutes or until crust is browned and a meat thermometer registers 145°. Transfer ham to a cutting board, and let stand 15 minutes before carving.