The most often mentioned is Django. We picked Tornado (tornadoweb.org) because it is lightweight and fast, especially on cold start, which is an app engine issue for low-traffic apps. It's even faster than webapp (!) because webapp loads the Django templating system. We've been happy with Tornado, although it doesn't have as much support for some stuff (e.g., web forms). It does have a templating language which is ju…
I've used tipfy.org