I just pushed Roundtrip, a Redis, Sinatra and Graphite based business process tracking and metrics service. You can also see how it works in this blog post.
I just pusehd FrenzyBunnies. A JRuby and RabbitMQ based background workers framework, targeting high-performance and efficient resource utilization use cases.
An evening's effort, here is an open-source, Sinatra based implementation of BoxJS/CSS/Resizer back ends compatible with Box*'s javascript libraries, including future Box* features - that you can deploy right now.