"Slug" is a nickname for the Linksys NSLU2, a small, cheap, low-power, ARM-powered Linux box. I use mine as a file server, print server, and general platform for experimentation. Here are some pages describing things that I've done with it:
SlugTerm is a terminal, consisting of a small LCD character display and keyboard.
SlugPower is a power switch that I use to turn my printer on when the Slug has something to print.
SolarSlug describes my attempts to power my Slug from a solar panel.
SlugBee is a Zigbee radio module, connected to my Slug, for remote data logging.