This is the single most important thing you will find inside Mandalay Bay, and I suggest you go here as soon as you check in. Booze... all of it. Wine. Beer. Mixers. Water. Soft drinks. Snacks. Trashy reading. Mags.
Anything you need to recover from partying, help continue partying, or start the... well you have got it.
I would start by picking up mixers, some bourbon and vodka, a bottle of wine. A newspaper you will not have a chance to read. Some snacks, a lighter, some smokes, a couple oversized beers you can't fit in your mini bar... and then keep going.
My gosh I adore this little hut of needs.