There is some buzz around the new open source framework for concurrent programming - Disruptor. It is an essential part of infrastructure for LMAX exchange.
Project's site at Google Code
Techical paper for Disruptor
Video presentation at QCon
LMAX was established to create a very high performance financial exchange. As part of our work to accomplish this goal we have evaluated several approaches to the design of such a system, but as we began to measure these we ran into some fundamental limits with conventional approaches ...
The Disruptor is a general-purpose mechanism that solves a complex problem in concurrent programming in a way that maximizes performance, and that is simple to implement. Although some of the concepts may seem unusual, it has been our experience that systems built to this pattern are significantly simpler to implement than traditional approaches ...
On processors at moderate clock rates we have seen over 25 million messages per second and latencies lower than 50 nanoseconds. This is very close to the theoretical limit of a modern processor to exchange data between cores.
Project's site at Google Code
Techical paper for Disruptor
Video presentation at QCon