Position an oven rack in the lowest position; preheat to 350 degrees F. Trim off any skin from the ham, leaving a 1/2-inch layer of fat. Score the fat with a sharp knife in a 1-inch crosshatch pattern without cutting through to the meat. Place the ham, fat-side up, on a rack in a large roasting pan.
Pour 2 cups water into the pan; tent the pan with foil. Bake until a thermometer inserted into the ham registers 110 degrees F, 2 to 2 1/2 hours, adding another 1 cup water to the pan if the liquid evaporates. Remove from the oven and uncover.
While the ham is baking, prepare the glaze (see recipes, below).
Whisk 1/4 cup of the pan juices into the glaze. Brush the ham with about half of the glaze. Return to the oven and continue baking, brushing with the glaze twice more, until the glaze is caramelized and the thermometer registers 140 degrees F, 1 1/2 to 2 more hours.
Transfer the ham to a cutting board or platter; let rest 15 to 20 minutes. Strain the remaining pan juices into a saucepan and boil until slightly syrupy. Spoon the reduced pan juices over the ham. Serve with any remaining glaze.
Before baking, arrange halved orange slices all over the ham, securing with cloves. For the glaze, whisk 3/4 cup light brown sugar, 1/2 cup dijon mustard and the juice of 2 oranges.
Before baking, arrange thinly sliced pineapple all over the ham, securing with cloves. For the glaze, simmer 2 cups pineapple juice over medium heat until syrupy, 7 to 8 minutes. Whisk in 1 cup pineapple preserves, 1/4 cup dark rum, 1 teaspoon mustard powder and 1/2 teaspoon each ground cloves, allspice and coriander.
For the glaze, simmer 2 cups pomegranate juice over medium heat until syrupy, 7 to 8 minutes. Whisk in 1/4 cup spicy mustard, 2 tablespoons red wine vinegar, 1 tablespoon chili powder and 1 tablespoon jalapeno hot sauce. Brush on the ham as directed, sprinkling with 2 teaspoons chili powder before returning to the oven. Add 1 cup pomegranate seeds and 1 diced jalapeno to the reduced pan juices.
For the glaze, boil 2 cups cranberries, 1 cup cranberry juice and 3/4 cup pure maple syrup with 4 thyme sprigs and 1 cinnamon stick over medium heat until syrupy, about 10 minutes. Remove from the heat and stir in 1 tablespoon chopped thyme.
Before baking, add 2 teaspoons juniper berries and 1 teaspoon black peppercorns to the water in the roasting pan. For the glaze, simmer 1 cup ginger preserves, 1/2 cup dry vermouth and 3 tablespoons champagne vinegar over medium heat until syrupy, 4 to 5 minutes. Brush onto the ham as directed, sprinkling with 2 teaspoons crushed juniper berries and 1 teaspoon crushed peppercorns before returning to the oven.
Before baking, add 4 rosemary sprigs to the water in the roasting pan. For the glaze, boil 1/2 cup each whole-grain mustard, honey and dry white wine over medium heat until syrupy, 3 to 4 minutes. Remove from the heat; stir in 1 tablespoon chopped rosemary.