
If you like cultural tourism Bilbao has a lot of things you to see them. For example, you can visit the Guggenheim museum, or the Old Quarters.
Then you can have a break and eat the typical northern spanish food(great meat, fresh fish, also good vegetables, spanish omelette...)
And, actually, at nights Bilbao is also a very live city, you can go to different places to have a good time, like shopping centers or even in Bilbao's streets.
Nevertheless, if you want to take a relax, you can also come an stay in a "caserio" in the mountain or spend some nights in a small beach camping.