How should I make a weekend in Lisbon special for my mother?

Hi there, I am going to Lisbon for a long weekend with my mother in May. She turns 50 that month and I want to make the trip as special as possible for her. We are staying in Hotel HF Fénix Garden. Some suggestions I have receieved include booking in for a spa afternoon, organising luxury transport from the airport or maybe asking the hotel to organise a small surprise for her. I would love to get your advice on ways that I can make the weekend special for her or even how to surprise her with an experience while we are away? Thanks in advance