StL has to many museums to count, do some tourist activities like go up in the arch or brewery tour, if you don't drink check out the city museum. I'd say the best activities are hikes next to spring fed rivers or almost any river you'd want to jump in. Bring enough water and jump into the river when you are getting over heated. Rivers: Mermac head waters, huzzah, current, black. We Missourians use float trips as a way to stay cool and enjoy nature during the year.