Dan sez, "Astromedia is a German science gizmo company that specializes in die-cut cardboard widgets: astrolabes, sextants, telescopes, etc. But this new one takes the biscuit -- a Stirling engine that works on the heat from a cup of coffee. Apparently, if you set it on a frozen compress ("Setzen Sie ihn auf eine Kaltkompresse..."), it runs for hours." Link (Thanks, Dan!) Update: Pschemp prepared
