"A group of ShipPlotter enthusiasts bring you live vessel movements from around the Irish Sea (and further!) derived from AIS data. Click on the map to see the individual ships, their statistics and photos."
Take a look at Dover with a 2 minute refresh. You can also click on each ship for details about the ship and its current journey. If you do that you can also link to the History of that ships movements, day by day, and even to a Ship Register.
Very impressive use of technology and a good insight into the importance of shippingh to the UK.
Now if you'll excuse me, I feel the urge to follow ships...