The minicluster, which I presently use for running simulations with OpenFOAM. These are Intel Q6600s with 2gb RAM. It consists of four diskless nodes; they boot with PXE and mount their filesystems from a host machine over NFS. They are mounted on cut-down ATX motherboard trays, tucked up out of the way under my desk in the main area of the bus.
A telegraph, attached to a USB port. Below is the touchscreen for controlling the house systems, in this picture not yet permanently attached. telegraph and touchscreen