I've published a demo webapp for mobiles written using Flask and jQuery Mobile. The backend storage is MongoDB. The app allows you to check and edit a shopping lists from your mobile phone so that if your fellow file the list from home, you'll have it at your finger tips later, when at the mall!
This has been deployed on OpenShift which offers MongoDB instances for free, as well as support for any Python WSGI app. Flask is installed using virtualenv, see https://github.com/gfidente/openshift-myshoppinglist for it and enjoy!