If you live in Chicago or the midwest and looking for a quick getaway, Silver Beach about 90 min drive from the city and a great place for kids. The Michigan side of the lake is so beautiful and you get to see the sun set on the west side. The beach has full facilities for changing kids, if you're going for a day trip. There's an outdoor play area in the sand where kids can climb when they get bored of the water. There's also a big carousel and indoor arcade to beat the heat when you need a break, and they have a huge outdoor water fountain that sprays water from about 20 different areas. Before heading home, hit the pizza parlor that's nestled in an old train depot. Parking is approx $10 and there didn't look like any area to rent umbrella's or chairs so make sure you bring your own. A great fun day for the kids, not too expensive and quick ride back into the city.
We were staying in New Buffalo but came up to St. Joseph area three days out of our 6. EXCELLENT public beach... great sand, excellent concession, excellent rest area, beyond FAB on beach playground and just a short few feet away and air-conditioned indoor carousel as well as HUGE (and I mean huge) splash pad. Not to mention a children's "goo" museum in the carousel area as well as a full children's museum just steps away. Plenty of parking / cheap as well as plenty to do in the immediate area (shops/restaurants).