Today is a ZAP Free Day at Discovery Gateway! THURSDAY, MARCH 14th is FREE Admission day! It will be open from 10 am to 6 pm. This is a great time to get out of the house and have fun with your kids. They have so many fun things to do there for all ages. AND you can get $10 off a family admission today only! Also opening on March 14th is their newest exhibit offering… the Imagination Playground.