Buying drinks at the bars in VIP and the club.
I'd love to see this, even if drunken effects aren't added. It would just be cool to have the ability to have one in your hand, as well as improve the general ambiance on the floor rather than having a bunch of people standing around looking at their cell phones.
It would also be cool if you could get table service and keep them on the table and perform emotes with them even if it's just taking the occasional sip. Having a variety of cocktails each costing 1-5 RP might work.