With paring knife, make a small X in the stem end of each brussel sprout. In a large pot of boiling water, cookd the sprouts until crisp tender, about 7 minutes. Drain well.
Meanwhile, in a large nonstick skillet, warm the oil over medium heat until hot but not smoking. Add the garlic and cook, stirring, until tender, about 2 minutes. Add the sugar and swirl in the pan until melted, about 2 minutes.
Add the vinegar, orange juice, thyme, salt, pepper and the drained sprouts, and continue cooking until the sprouts are richly glazed, about 5 minutes.