habitat. Kids discovery museum at the smith center. I don't know exactly what it is called, but it is a hands on kids museum like most cities seem to have. Shark reef at mandalay bay. Birds at the Flamingo. Mob museum if your kids are a little older. Titanic exhibit. Bodies exhibit. Wax museum. Avengers thing at the treasure island (although it is way over priced). There is a lot to do. Very little to do for free though.