I like to just wander around when we travel, so we did lots of just wandering around. The streets of Pisa are filled with people walking and bicycling- bike everywhere. We walked through some of the main streets, some narrow walkways, and along the river's colorful buildings.
Lots of good thinks to see in the windows too.
And of course, we had to see the leaning tower and make the obligatory posed photos (hehehe).
We made our way there early in the evening and the daytime crowds had thinned out by then, so it was actually quite nice.