Everytime we come to Vegas, our first stop on the Strip is a to Fat Tuesdays at The Forum! It's right next to an Express store. The boys usually get the 1/2 Yard or Yardlong alcoholic slushies with an extra shot. I take sips here and there and it's really delicious, I almost forget there's a bunch of alcohol in there sometimes... try the Peach Bellini one!
Don't forget to save the plastic bottle so you can get cheaper refills later on!