JCGrid is an easy-to-use tools for real-world grid-computing. It requires only to install JavaRuntime and you can easy split your cpu-intensive task among several Workstations/PC/Mac/etc. It includes support for POVRay and MandelGrid as usage examples.
The iChilli mobile J2EE platform provides a J2EE compliant runtime environment for both server and mobile platforms, such as J2ME, MIDP or other CLDC based devices. For example iChilli runs on the PersonalJava enabled Sharp Zaurus and Compaq's iPAQ.