In this current economy many night spots, clubs, pubs, and coffee houses are struggling to find working formulas for increasingly slower weeknights. Consider having a drum circle night. It quickly builds up a solid community around it with a loyal following that grows very fast.
Your cost is minimal to have a drum circle night, I've been doing this successfully for years at various venues. What's really needed is an organizer to help keep things running smoothly, and promote the drum circle. Hire a local percussionist, circle facilitator, or maybe even a drumming group. Just Google "drum circle" in your area to find a few. Offer them a base pay or a percentage of sales like 10%, and try it for a few months.
Consider paying them a small base pay. Because honestly, there really is a lot of work involved. Also it isn't the drummers, musicians, or dancers that do the majority of buying your products. They will help support your venue and buy 1 or 2, but it's the onlookers attracted to the scene that will do most of that for you.
My experience is that charging a fee, or cover charge to get it established just doesn't work. Weekly or monthly? I recommend weekly drum circles to really get it established. With monthly circles people tend to forget what week it's being help on. If it's weekly, they know it's always there when they feel like going. Most people will go once or twice a month, some won't want to miss a single night.
A drum circle is kind of like having an open mic night, but better. Since it is interactive, everyone in the venue can participate. So rather than just sitting and watching a band or show, people can be a part of it. I would put out tambourines, maracas, and etc. out on the tables in wicker baskets to entice those who may think they have no rhythm, to get involved. Obviously this also retains the crowd longer because they have more fun.
It takes a few months to get a drum circle community built up and rolling. I go into all of this in much more detail in my book, "A Practical Guide To Hand Drumming And Drum Circles". Please consider picking it up, you would be buying direct from the author. (me) It's self published, 300 pages, and the price is $18. A drum circle jam CD is included with purchase from my website drumcircles.net
It would help out a little. Thanks for supporting independent artists.