Tubetown is a neat indoor playground that has all kinds of things for kids to do. Things to climb, crawl through, run through, video games, and pizza. We took our younger daycamp kids here last summer and they had a blast. Even the staff had fun crawling through the tubes chasing the kids around. There are also tables where you can sit and watch your children while they race around inside the huge structure.
Word to the wise: If you plan on crawling through the structure with your child, bring kneepads. :)