Take the old tram 28 (the stop is 100 meters away from our Guest House) and walk through all parts of the old districts.
Try the Pastel de Nata, the famous one is near the Jerónimos Monastery but I also recommend the Pastelaria da Manteigaria.
If one day you want to hear Fado and if you don't want to have dinner, go to Tasca do Chico and have a glass of wine, for example. All Fado restaurants usually start at 8 p.m.
If you have time, go to Sintra and visit (Sintra Palace and Quinta da Regaleira).