Photo: Wikimedia CommonsPapa Joes Klimperkasten is a beloved old-town institution crammed with antique instruments and lit by Tiffany lamps, where live jazz and ragtime play most nights amid a genuinely joyful crowd. It is atmospheric, unpretentious and free to enter. Squeeze in early for a good spot, order a Kolsch, and let the live music and the sing-alongs carry the evening.