web.py is still my go to for lightweight webapps. I won't start a big discourse on the pros and cons vs. other technologies, but I will say it is incredibly easy to setup and use.

The current github page is here: https://github.com/webpy/webpy

If you are looking to get up and running quickly, I would recommend forking this skeleton: https://github.com/jzellman/webpy-skeleton

Finally, the built in database framework is a bit simplistic. I like to pair this with Peewee (included in the webpy-skeleton).