I would have to suggest that if you didn't want to be stuck inside on a hot Vegas day and you wanted to have some fun with out getting to hot that Tao Beach seems the place to get it all.
Seems to be a good place to be on a hot day in Las Vegas and with it being a desert you know there are plenty of very hot days to deal with.
I won't say that this is something that I would do personally, but I know many of my friends would. I guess I am more the type of person who prefers to be inside on hot days,

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Though check out this video for yourself.