I had a similar situation a few months ago. My goals were to get something up and running relatively quickly but it was my first python web app and I wanted to make sure that I actually understood what was going on underneath the covers. I used web.py (http://webpy.org/). Overall I've been pretty happy with it -- it is small enough that looking at the code is actually meaningful to me (although there is definitely some strangeness in there from my perspective) but I also can mostly just write the app and not think about the framework.