After the rather lackluster The Other Place, the usually metronomically reliable Boulder Ensemble Theatre Company (BETC) comes back strong with Bach at Leipzig. If you enjoyed the movie Amadeus — and if you haven’t seen that film I can’t recommend it enough — you’ll revel in this jaunty, cheeky, fictionalized look at the cutthroat competition to assume one of the highest posts in the rarified world of music in Germany circa 1722.