If you haven't been to the Asian Art Museum you really are missing a treat. Not only is there some fascinating art that dates back centuries -- CENTURIES!!! -- but it sits in the lovely Volunteer Park. You could spend a whole day roaming the grounds, enjoying the grounds, the reservoir, the water tower, and the conservatory.
Both Heather and I are interested in photography, and we're thinking about having a photo shoot one Thursday a month. Volunteer Park will definitely be on our list.