H.W.
I have a 'bulldozer' in my neighborhood, who will trap M. in conversation if I let it happen. What's worse is that it's not that she's talking to M., it's that she's talking to *anybody at all*. (non-discriminatory bulldozing?:))
At this point, I will stop and talk if it seems like there's some back-and-forth happening, but if it isn't, I always have something else which needs doing and politely give her my regards and go on with my business. I'm really not missing out on the non-stop oration!