The Disruptor, the design pattern at the core of the financial exchange I'm helping build at LMAX has been open sourced. If you've seen the presentation that Martin Thompson and I gave at QCon or the one I did for the LJC @Skillsmatter, this is the ring-buffer based code that we've been banging on about for a while.
What is the Disruptor?
At its simplest, it's an alternative to a queue, but can also can be thought of as a simple actor-like concurrency framework.
Performance, it's about 8-9 times higher throughput and 3 orders of magnitude lower latency than Java's ArrayBlockingQueue. There's a technical article on the Google code site with more details of the implementation and comprehensive performance test results.