Marian, Moon Marbles it is, one of the happiest places on Earth for kids of all ages. The owner is a great fellow by the name of Bruce Breslow, and every year on the first weekend in March he hosts his Marble Crazy event.
https://www.moonmarble.com/t2-annualevents.aspx
And, conveniently, that same week the Kansas City marble show takes place:
https://marbleconnection.com/topic/24134-kansas-city-marble-show-march-3-2019/
Scott McBride and company put on a great show. I guarantee if you go you’ll have a both a fine time AND be able to learn more about marbles in a couple of good days there than you’ll pick up from pictures. Go early to the host hotel, visit some of the exhibitors in their rooms, ask questions, and you’ll be amazed at what you see.
I’m typing this now at the Canton, Ohio Show, and the halls of the Holiday Inn are filled with happy marble people doing just that!