I would think 1 of the local outdoor bars would accommodate you. 1) They're already loud-ish, 2) They get your drink business, 3) You'd probably draw curious spectators who would then drink, 4) Once established as a place, time, event, you may even get larger participation.
Make arrangements with the owner and manager for a slight discount on volume drinking and a cordoned off area for suedo privacy from wandering drunks.