Go to the nearest park and wander about and just talk Source:
Is there nice weather outside? Then why stay cooped up inside, when walking fills your brain with oxygen and new ideas 'off the trodden track'. Get outside and take a walk in the nearest park. Talk will naturally revolve around work. This is a nice break from routine when things run relatively smoothly and you don't need visual documentation to support discussion. Mature teams can easily spread ideas and reach consensus even in such an informal setting.