Fat Tuesdays are abundant in Vegas. There seems to be one in every major casino/mall/whatever.
There's good reason for that. Their blended boozey slushies are effing great. I ALWAYS get the Octane with an extra shot and I am never disappointed. For Strip booze prices, they are very reasonable.
I know it looks like so much fun to get a yard of slushy booze, but I don't recommend it.
The basic size (with extra shot....always get that extra shot!) will make you feel good and you don't have to worry about forcing yourself to gag down hot, melted, rum, sugar sludge when you get to the bottom.
There's just too much dang sugar in those huge yard-long drinks. Only get one if you intend to recycle it and MacGuyver it into a bong later on.