From the provided data, it is not explicitly stated what the leisure amenities are at Aparthotel Siegen. However, based on the fact that it is an "aparthotel," it can be inferred that guests have the option to stay in spacious apartment-style rooms, allowing them to relax and feel at home during their stay.

Additionally, since the hotel is located in a central area and is close to public transportation, guests may have the opportunity to explore the surrounding area and enjoy nearby attractions and activities. It can be assumed that there are nearby restaurants, shops, and cultural sites that guests can visit during their stay.

Overall, guests at Aparthotel Siegen can likely spend their time enjoying the comfortable and spacious accommodations, exploring the local area, and indulging in the various amenities and attractions that the city has to offer.