Trim brussel sprouts of limp leaves, then cut an "x" in the base of each stalk. Bring a large pan of water to a boil, add sprouts and back back to a boil. Boil 1 minute, then drain and run cold water over until cool. Cut sprouts in half. In separate skillet, saute Bacon 3 minutes. Add garlic and saute til Bacon is crisp. Add sprouts and saute til warmed through. Pour in beer and bring to a boil. Simmer till sprouts are crisp-tender, about 3 minutes. Season with salt and pepper. Place in gratin dish and reheat, covered at 350f for 10 minutes or till hot. Or leave in skillet and reheat in it.