Park Place - A recreation of the Amazon S3 API, but hosted on your own machine. In Ruby. Perhaps not entirely uninteresting after the recent 7-hour outage - for example, you could run a mirror of the data at Amazon on your own box and, in the event of longer outages, switch to your own copy within your own software to at least remain rudimentarily functional during S3 outages. Or even build your own server structure based on this and turn your back on S3.