Once upon a time, a Marvell developed a product called the Sheevaplug to drum up interest for their "Kirkwood" ARM-compatible CPU line. This was a complete linux system hidden in a wall wart, whose design they gave away as a reference. This led to a number of Sheevaplug-based devices hitting the market, including the PogoPlug, a line of cheap NAS devices which are all based on the Sheevaplug design with various single-core Marvell CPUs. They are now discontinuing not only that line but also the service for the same, so the devices are cheaper than ever before right now, and this is a great time to pick one up — I got one for $13.
Once I bought a dockstar, and was mightily annoyed by it. Eventually new Pogoplugs came out, and I invested a whopping nine bucks in a used pogoplug mobile. After having it deregistered by support, I tried installing ArchLinuxARM on it. This produced a brick with a flashing green light, so do not try to install Arch for ARM on this device. It's probably possible to make it work, but the default install instructions don't work. Further, the revert process didn't work either! Seems like their u-boot is broken for this device.
The dockstar doesn't have an RTC to keep costs down. If you're running Debian Squeeze (and you probably should be) then you can make the following tweak to /etc/init.d/ntp to use ntpdate (which you should also install) to set the time before running ntp.