Every time I land in Vegas, I make a beeline for the nearest Fat Tuesday. Although I am getting older now, so I have to make sure and pop an acid reflux pill first.
Not all the locations have it, but the Electric Lemonade is my absolute favorite. Get an extra shot of rum in the half yard and you will be good to go all day! The slushee is nice on a hot day, and the prices are reasonable for the amount of alcohol that you are drinking. Cheers!