I once hacked together a simple dos-style commandline for the psion 3a during a university lecture. It could only do basic directory listing, browsing, copy & move, but it looked the part - full screen a small font.
Oh, and I programmed pong for the 68008 with pots for input and an oscilloscope for output. Not that hard using a dev board, but there was something cool about playing it on an osc.
