Simplest framework for converting python app into webapp?
+1 for bottle. 
Nevertheless, consider that the scope usually grows when developing web apps and that text box and those 2 buttons will later on need: templates, lots of routes, maybe translations, etc. So, always consider using something that would allow you to move into some powerful framework such as web2py or Django.
I have a small python app that I would like to convert into a webapp. I have look at some frameworks out there such as django.
I need some suggestions on a very simple framework. All my webapp will have is a textbox and two buttons.