https://github.com/hyunwoongko/openchat (https://github.com/hyunwoongko/openchat)
Here's a nice Python library that lets you download and try out a number of near state of the art chatbot systems based on neural network models. It's pretty simple to use but you will have to wait while it downloads many gigabytes of data and software. The libraries themselves were about 1 gigabyte and the blender library that I tried out was about 4 gigabytes. I was running it with python3 and pip3.
pip3 install openchat
python3
from openchat import OpenChat
OpenChat(model="blender.medium", device="cpu")
It doesn't get much simpler than that does it. :)
Check out the linked page for a demonstration and a lot more examples.