The Knowledge Cafe and World Cafe are two such tools. But you can also include peer-assists, after-action reviews and post-project reviews in the list along with tools such as Open Space.
Collectively, I refer to these tools a "Conversational Cafes" as they are all about face-to-face conversation.
But there is another conversational tool that is far more widely known and used than any of the above and that's the
brown bag lunch
You are not familiar with the concept then quite simply a brown bag lunch is an informal training or information or knowledge session during a lunch break.
The term brown bag comes from the fact that in the USA meals brought along by the attendees are often packed in brown paper bags.
Robert Dalton reminded me of brown bag lunches in a recent post on the Gurteen Knowledge Community Forum on LinkedIn.
From a knowledge management perspective, a brown bag lunch isYou can find more information here:a structured social gathering during an organizational lunch time period which is used specifically for the purpose of transferring knowledge, building trust, social learning, problem solving, establishing networking or brain storming
Credit: Bob Dalton, KMnet
They are an excellent way of stimulating informal conversation and connecting people but note they do not have to take place at lunch time, they can take place during any break including breakfast and a brown paper bag is not a requirement!