When you're brainwashed with a variety of TV series, movies and pop culture, it's good visit a high culture place, like a museum, from time to time (at least, that's what my girlfriend says :) ).
The first museum that we visited (out of two, the second museum we plan to visit is a photography museum) was the Porto's Art Museum. The most interesting, in my very personal and subjective opinion, was the sculpture exhibition.
FYI: All the pictures were taken with an iPhone and edited on an iPad.