There's....
Como Zoo in St. Paul
Grand Ole Creamery on Grand Avenue in St. Paul is another place we never forget to stop @ while visiting the in-laws.
St. Paul's Children Museum My kids enjoyed visiting here.
Science Museum of MN Another great place to visit.
I'm sure some people who ACTUALLY live in this area could tell you some more things, I just wanted to give my suggestions as a fellow MSP visitor.
Enjoy your visit there. We're hoping to get there this summer!
-gina