It's hard to find an indoor water park that doesn't feel suffocating, but Silver Rapids has a glass roof and lots of ventilation. I never felt like it was stuffy. More to the point, the kids loved the lazy river and surfing section. My kids don't do slides too much, but those looked fun, too. There are large hot tubs, and a bar upstairs (kind of un-classy, honestly, as the adults get loud up there). The downstairs food counter serves the junk food you'd expect, like nachos and burgers, but definitely try their huge sundae!
We usually spent a few hours at a time here, in between outdoor activities, and used the outdoor hot tub by the lodging area as well.
I was dubious that we would have an enjoyable time here, because my youngest two kids weren't THAT keen on water, and didn't really like to leave my side. They loved it! The slides for the littler kids weren't too scary, they were having fun in no time! They provide life jackets, and towels, but you have to pay for a locker for your items. My kids ask to go back all the time!
They have several levels of slides, large ones you have to climb many stairs for, family slides, where you can go down with 4 in a tube, racing ones, where you can compete, and many many many child size slides....little ones for the tiniest of kids. They have 2 toddler only areas, great for littler kids. They also have a wave simulator, which was good for even my 6 year old!
They also have the bucket that fills up and dumps out every so often. There was something for every age level here.
Silver Rapids is an indoor waterpark owned and operated by the Silver Mountain Resort. Book one night at the resort and the whole family can swim for 2 days. The larger rides are made for the whole family, even toddlers! Our son enjoyed the water basketball cove and the lazy river. Our room at the resort had a kitchenette. We enjoyed the waterpark and then went to our room for lunch. There are vendors in the waterpark, but we were on a limited budget. Outside food is not allowed in the waterpark. The resort also is at the base of Silver Mountain. There are packages for families to ski and swim. Also, the resort is near the Hiawatha Bike Trail. http://www.skilookout.com/hiaw/