Preheat the oven to 425 degrees and boil a big pot of water.
Cut the potatoes into bite-sized cubes, and add them to the boiling water. Boil for 5 minutes, then drain them.
Place the potatoes, along with the peppers, mushrooms, garlic, olive oil, and salt in a large roasting pan. Stir the mixture to coat evenly with oil.
Roast for 30 to 40 minutes, or until the vegetables are all tender. Stir every 10 minutes.
Remove the vegetables from the oven and pour the red wine vinegar over the warm vegetables. Taste the vegetables, and add a little more salt or vinegar if needed. Sprinkle with fresh chives and/or other herbs. Serve warm or at room temperature.