GridGain + Multi-Core processors
GridGain is an open source product written in Java providing a grid computing platform. It is known to be one of the more widely used grid product, certainly, as far as I see, one of the easiest to "gridify" or grid-enable an existing product.
The widespread use of "multi-core" PCs also means that the product can be used to "parallelise" to take advantage of this increased power.
My setup involves one "broker" node and three "worker" nodes. The grid job is sent from one of the worker nodes.
I use ActiveMQ for communication between nodes, GridSharedFsCheckpointSpi for saving down intermediate data (to be picked up during the "Reduce" phase) and JobStealing SPI for automatic load-balancing and failover.