The Arduino microcontroller which uses the Atmega168 Microcontroller is an amazing chip to work with. One of the features it can do I read and parse NMEA data string outputs. I would eventually enjoy using the Arduino to process NMEA data and convert it to AX.25 packets to transmit to the amateur radio APRS system. This would allow me to track anything I want remotely or use the GPS for other uses.
My main goal is not APRS though. I have been increasingnly interested in UAV's and robotic applications. I found a really fun website called DIY Drones. This website shows many projects where people use the "ardupilot" which is essentially a modified Arduino with autopilot coding loaded on it. I would enjoy experimenting with controlling a remote control airplane or other flying object (ballon, RIT blimp?, etc).
I acquired these GPS modules which I believe come from Tom Tom Go 510 GPS units. I have about 10 of them and have been experimenting with powering and getting data from them. The main problem is that they seem to be proprietary and I cannot find any information about them. This means that I have to reverse engineer the circuit and figure out which pin on the connector or trace near it is power, ground, data out, etc. I have not had the time to experiment with this too much yet but I believe that by using the datasheets on the chips used in the circuit, I have been getting very close to properly identifying the leads!