For my 30th birthday, the surprise was to go to Lisbon. I have to say that although the city is not that young and vibrating, I found it beautiful, definitely worth of spending that important weekend there.
We stayed at the York House (www.yorkhouselisboa.com) on Rua das Janelas Verdes. This charming boutique hotel was once an old Carmelite convent and the rooms decoration recreates the elements of 17th century architecture.
My favorite things in Lisbon: taking the tram to the Castelo de Sao Jorge in the hilltop Santa Cruz disctrict, going for a drink at the Pavilhao Chines Bar on Rua De Pedro V near Bairro Alto. This bar is similar to none, and make sure you look around and turn around and look above your head...this is a real Ali Baba cave!
Of course, you can't go to Lisbon without: tasting the Pasteis de nata (custard pastries) right outside of the Mosteiro dos Jeronimos in Belem
and, treat yourself to a typical Portuguese dinner with the unique Fado singing. Fado (destiny) is a traditional Portuguese music and there is nothing better than to hear it live. We actually tried a restaurant by our hotel Sr. Vihno on Rua do Meio à Lapa, 18. It was fantastic, apparently one of the best in town and the most authentic. It was indeed very unique and the music of course...very sad! Be careful, it is easy to miss it on that street since it is mainly a residential area and the entrance is discreet.
For one of the three days we spent in Lisbon, we decided to go to the hilltown of Sintra close to the coast. Sintra is recognized as a UNESCO World Heritage and although it draws many tourists all through the year, there are still many quiet walks around town. 
On the coast, if you don't have time to go all the way to Cascais (we didn't!), try to visit Cabo Da Roca right after the village of Azoia. In this tiny village there is an amazing restaurant called Refugio da Roca, serving delicious seafood and Portuguese wine. The place looks like a Swiss chalet in the mountains but it's definitely worth a lunch before visiting the lighthouse at the Cabo da Roca.
