At our family cookouts I treat conversations like the shared Netflix queue. When an episode drags, you hit next with a smile and a wave. Try a quick you two have been awesome to chat with, I'm going to circulate before the potato salad disappears, and pivot your hips toward the exit. If they keep rolling mid-story, toss in a to be continued and point to the person you need to catch. Works great on uncles and neighbors, less great on toddlers.
