The Smooks project has been around for a while but probably started to come to prominence when JBossESB used it as the default transformation engine. Over the last year we've seen other open source ESBs also add support for Smooks transformation technology as well. However, as this InfoQ article from Tom Fennelly, the Smooks lead, shows Smooks is capable of much more than just transformation.
Read Structured Event Streaming with Smooks on InfoQ.