This bizarre museum offers a one-of-a-kind entertainment experience by blending endless fun for children with constant surprises for adults. How do you describe a place with no qualms about combining a Baby Ball Pit, the Museum of Mirth, Mystery and Mayhem (showcasing the world's largest pair of men's briefs) and a serious exhibit on architects Louis Sullivan and George Grant Elmslie? You'll find a shoelace factory, a collection of vintage opera posters, MonstroCity, Enchanted Caves and a salute to Corn Dogs Through the Ages. One room celebrates the Beat Generation, another contains just a single piano. It's easy to spend hours just wandering around. If you really want to make it a full day, take a trip to the rooftop, which offers not only a fantastic view of St. Louis but a chance to ride on a four-story Ferris wheel, take a turn down a slide and climb inside a bus that's teetering over the building's edge (admission is $5, not included the $12 museum ticket price). Or check out the World Aquarium, which is an extension of the St. Louis Children's Aquarium (you'll pay an additional $6, well worth it for a chance to crawl through the shark tank's glass tunnel). Circus Harmony, a circus school inside the museum, gives you a taste of big-top life via classes teaching juggling, trapeze, tight-wire balancing and the like. Visitors can watch classes in session or attend circus performances held every day except Monday and Tuesday.