The NSLU2 from Linksys is a small, sub $100 device that can be used for a variety of tasks. NSLU2 stands for Network Storage Link for USB 2.0 Disk Drives, a description which pretty much summarizes the original purpose of this device. However, the NSLU2 (or Slug, as it's often referred to) can be used for other tasks if you use a more powerful firmware for it. Since the device offers two USB ports, it's possible to connect a USB disk and run a full Ubuntu system on it.