Circus Circus Las Vegas seems to be the main kid attaction in Vegas. It has a huge theme park inside a dome behind the casino. The theme park has a double corkscrew, double helix twist roller coaster and I believe it is the only indoor theme park in the country, if not the world. When I was younger, me and brother spent an entire day in the dome with our all-day passes. The best part is, during the week there are NO LINES. That's right, there is NO WAITING TIME to ride the rides.