The librarian before me used to sell hot chocolate to the sudents. After surveying the students at the end of last year this was one of the most requested library events that the students wanted to see continued. I also read about other similar programs here, here , and here on the Blue Skunk Blog.
I have continued but with my own spin. We have expanded our menu options to include hot chocolate, French Vanilla Cappuccino and hot cider. I wasn't sure that middle schoolers would choose cider over chocolate, but there were students that actually did a little dance of joy when they saw it on the menu. All of the drinks are 50 cents. We have marshmallows and cinnamon as free toppings. I have created a cafe style seating area with four round tables near the circulation desk. I am lucky/unlucky to be in a very old building so there is a sink in the library office for some reason. I'm glad it is there. I keep the materials in the office and I have student helpers and book club members making and serving the drinks. I ask that students sit at the tables to be waited on to avoid spills from walking around. I have new carpet so I'm trying to preserve it as long as I can. They actually like being waited on so I have had no complaints. So far I have only had one spill and we were abe to clean it quickly with minimal damage.
This has been a great way to bring lots of kids into the library, create a place where the students feel welcome and comfortable and it raises a little money for us. My experience has been a good one and I would recommend others give it a try. Just FYI I do not have an aide/assistant, but I am able to pull this off because of some very hard-working, motivated students.