http://en.wikipedia.org/wiki/City_Museum
its about a block from where my sister lives, you can spend a DAY there.
http://www.magichouse.org/
for the younger ones
https://www.stlouis-mo.gov/government/departments/parks/parks/Forest-Park.cfm
St Louis Zoo, Art Museum, Science center, History Museum and Muni Opera all free admission, some pay areas. part of the deal with Forest park being willed tot he city was that it had to reamin accessible and free to the common man, so most of the attractions either have free seats or admission with pay for special atttractions.
if you are picking up in Elkhart and running south Indy has some great attractions as well but i am not as familiar with them.
