How about walking in a local park, or throwing a frisbee? Taking a group walk can be a good way to get to know new people, and it seems natural to walk and chat

How about walking in a local park, or throwing a frisbee? Taking a group walk can be a good way to get to know new people, and it seems natural to walk and chat with someone for a little while, and then switch partners. Groups can easily change membership/size without the disruption of needing to change chairs around a table.