Software for Hardware Demonstrations?

raarky asks: "My company will be running a stand at a rather respectable geek conference and I would like to ask the developer and sysadmin crowd what sort of demonstration software would be cool to see running on some of the highend server, workstation and mobility (notebooks, handhelds etc) hardware we have available. Ideally it has to appeal to the intended audience and show off the capabilities of these systems (read: intensive). My first thoughts were something like a renderfarm or some great open source 'end to end solution' that crunches lots of data and has client software to display the results." What software would you use to show off hardware capabilities?