My buddies on Twitter pointed me to a really cool application of location-based services. The site is www.shipais.com which shows the position of commercial vessels in the vicinity of the British Isles, in real time.
Very entertaining. In closeup, the application also provides some basic information (source-destination, etc) about the vessel as you click on it.
I've used a similar service at www.flightaware.com to track aircraft in the Boston area as they carry family members to our home so that we can correctly time our departure for Logan to minimize the wait time at the airport.