It sounds crazy, though the format makes some sense. The group takes a minute or two to write down some ideas on paper. Each person then gets two votes to place against the topics. The top rated items get discussed first for a period of time and at the end of that time, everyone votes on continuing discussion or moving on. This can repeat every few minutes.
I got the chance to experience this at the recent DevOps Enterprise Summit conference, where there were Lean Coffee breaks every day, with each having a topic that people wanted to discuss. One I participated in was fairly rigid, with the facilitator keeping to time, gently encouraging discussion, and rigorously calling for votes.
While I enjoyed that, a second one didn’t use timers consistently or votes, and the meeting ended up being a rather free form discussion, which was OK, but it meandered and wandered without guidance in a way was somewhat annoying. It was a surprising experience for me, as I typically like free form discussions.
I don’t know that I’d recommend Lean Coffee for all meetings, but I do like the format, and I think this can be a good way to focus on a few areas a team finds important, especially when there isn’t a clear set of priorities.
I would encourage you to give it a try, especially if you get into a meeting without a clear agenda. Maybe it’s something I’ll try as a way to discuss and debate some topics at some event.