the old palm pilot you have could also be used as the brains for a nifty little holonomic drive robot. the palm pilot robot kit was created several years ago by the carnegie mellon toy robots initiative. that would be the same research group that came up with the bow powered pogo stick.
The Palm makes a handy robot controller: it packs a lot of computational power in a small size, runs on batteries, and best of all, can display graphics and an interactive user interface. Our robot empowers a Palm to move about and sense the nearby environment.
speaking of palm hacks, sean russell sent me this link after reading the palm lcd display article. make sure to check that out as well if you are interested in dusting off your old palm device.