Richard Haberkern has created a Kickstarter project for an Arduino compatible GPS data logger. There are plenty on GPS loggers out there, but the GPS Cookie is based on the Arduino. This means users can create their own firmware and edit the Cookie to suit their needs. The beauty of the project is that you can edit the firmware, hook up various components, and run it from 2 x AA batteries.
As you'd expect from a GPS logger, the Cookie stores your data to an SD card, and you take the data off the card and upload it to your computer. You can then load up your trip into Google Earth, or other map software, and track your trip. The Cookie stores all the basic info; speed, direction, dates, times, route, location and altitude.
Among typical uses such as logging your exercises (jogging and cycling etc.) and tracking your commute to work to find a shorter journey, you can also geotag all your pictures if your camera doesn't have the feature. As you can edit and add to the Cookie, you can create all manner of interesting projects.
The Cookie comes in 2 shapes; the Cookie is round, and the Sandwich is square. Apart from the shape, there is nothing different between the two. The project is live now on Kickstarter, where a $79 pledge will get you either shape without USB (which you can add yourself later).
EDIT:
The campaign has ended. Read more at the GPSCookie website.
You can watch the Kickstarter video below; just ignore the creepy thumbnail!