Figueira da Foz is a lovely coastal city, right smack in the middle between Porto and Lisbon. It is easily accessible by public transportation (train & bus). It is a little off the beaten track, so it is not yet overrun by mainstream tourists. There is one exception though, because the first two weeks of August people from villages more land inwards will spend their summer holidays on the beach in Figueira da Foz. And rightly so.
Regardless, the town is beautiful: with little squares and parks, hidden away in the myriad of little streets. Streets lined with trees that display lovely flowers most of the year. The buildings are mostly typical Portuguese architecture, especially the old city centre. The tiles on the outside of the old buildings are a beautiful sight to take in, and common, if not unique, to Portugal.
Be sure to visit the market (Mercado Municipal) to get the best deals on local produce and fish. And if you sit down in one of the typical coffee places, don't forget to try the pastries. Portugal has the best bread in the world (no joke).
Figueira da Foz is home to one of the biggest beaches in Europe, due to the long pier. The new walkways on the beach make it easier to reach the ocean, or just go for a stroll on the warm summer evenings.
You can also ride your bike along the ocean side towards the cape. The bike path is pretty decent (and I am Dutch, so that is saying something) also fun with a longboard. It will take you out of the Figueira centre and lead you along Buarcos and eventually towards the cape Mondego. You can even go up the cape and find yourself in a vast forest, filled with eucalyptus trees. Be sure to check out the vista point, that looks out on the other side of the cape: Quiaos.
As for nightlife, it is best to visit in the high season (or with the yearly festival on the beach: Somnii, organised by the Portuguese radio station RFM), as all bars will be open almost every night. In the months around high season, most places will be open every weekend.
Surfwise Figueira da Foz is relatively undiscovered and definitely less crowded compared to the more southern beaches around Peniche. The ocean is still the same though, so the waves are pretty decent most of the time, can get scary when serious swell arrives and will be mostly cute during the summer months.
Enjoy the weather, that is always better than surrounding towns, because of the meteorological advantages the cape provides. Because of the same reason it will also be foggy from time to time, but that will always clear away as the day progresses and may lead to the most beautiful pictures. The sunsets are hard to miss, and you really shouldn't miss them. Sunrises are pretty spectacular as well, but perhaps harder to witness ;)