Look on my works ye mighty.
These are some tutorial and book demo apps I've forked on Github and deployed to various free tier clouds. It's a snapshot of my pilgrim's progress to PaaS. No code fu here, folks...
Some of these I had to hack into shape, some are almost verbatim from the source, with a few cloud-fitting tweaks.
Backend: The top few of the below sites use Mongodb, the bottom few are on Couchdb and the middle mobile pair use PHP and local storage. The Rails one uses the standard PostgreSql on Heroku.