You know you've been to Vegas too low to start searching for thing to do outside of the strip.
I have two boys and we pretty much have done the kids stuff at the strip twice or five times. So it was off to visit other places and we GOOGLED kids museum and came up with LIED Museum.
The place would be okay, but it is in the same building as the public library and community service center. There were a lot of NOMADS just hanging outside and/or at the community service center just watching TV. Some off them look a little bit lost and confused and even my boy made a comment about how they smell.
Once you get past the vagabonds it's not that bad. Local school children were running around the place and my boys enjoyed interacting with the kids.
The cost was a little bit high, but then again they need to make money, but they do offer AAA discount. Overall my experience was "Meh. I've experienced better."