If you are staying at Wynn, make sure you contact the concierge and reserve tickets for XS. My parts had tickets and entered without waiting in line or any trouble. Drinks are expensive so be prepared to throw down - or do some major pre-partying.
There are blackjack and poker tables outside - the dealers are used to dealing with intoxicated patrons, so don't be afraid to step up and play!
To buy a table at XS is ridiculously priced - get there early and find a place to sit/stand.