The arduino has the ability to digitally turn things on or off, Check digitally whether something is on or off, and it can measure low analog voltages. That means you can use it for home automation, science projects, automatic plant watering system, an autonomous vehicle, or laser harp and a host of other uses. Traditionally you could do this with a computer, but for the inexperienced that can be daunting.
Note: I have it working on Fedora 16 and 17 also.
Seeed now is carrying arduino products at a more resonable price for the daughteroards. Bought the Seeed ethernet adapter and it works on both the arduino and the osepps boards also.
Added information about using the Nexus 7 as a terminal.
Step 1: Getting information for the Uno.
Make: magazine (aka makezine)
Robot Builder's Bonanza, 4th Edition by Gordon McComb