make sure you see bubble gum alley, which, as the name implies, is an alley covered with gum (and other stuff like photos and other ephemerata.) It is on Higuera St, just North of Broad St.

And of course there is so much else to do in San Luis Obispo. Hiking, biking, etc., Bubble Gum Alley is just the icing on the chewy chewy cake.