I'm so glad to have visited while on our last trip to LV!!
My son is 3 so we don't have a whole lot to do after the first day.
This place was only a few miles from the strip and definitely a nice change from adventuredome and arcades. Not massive but kept us busy for a couple hours.
Parking (garage, not lot) was free and not packed. Price was $14.50 per person which is not that bad.
This place had a tower where kids can climb and each "floor" had little things to do, like putting gears together and seeing how it works, slides to go from floor to floor, arts and crafts, and a economy simulation with a bank, grocery store and stuff.
Some awesome stuff. Would definitely visit again.