I've been experimenting with GPS tracking apps on my Droid recently. My interest in trip tracking started with my motorcycle trip in '06, where I wrote a custom ASP app to (manually) log waypoints. Tracking technology is much more readily available now, and the next time I do a road trip, I won't have to manually enter waypoints.
This set is from a few days ago, driving from work in Framingham into Boston. (I usually go south on 95 toward home, but that day I took 90 east.) It's logged with the GPS Tracker app by Instamapper. Their service isn't ideal: they claim to have KML export but I don't see it anywhere, for example. I think to use it properly I'd need to code an app on my end that pulls tracks from the API in real time, so I'm scouting for easier alternatives.
In the meantime, this is a screenshot from my Instamapper account, (with the map enlarged via Firebug), showing the heavy traffic that day. Each track is 30 seconds apart, with the trip taking a little over an hour: