I'm always amused by the Hawaii one, and usually ask people why they thought Japan attacked Pearl Harbour and no reinforcements came if it was so near the mainland USA.
I did astound someone in a pub a few years age who said Australia was about the dsame size as Miami, I said it was about the same size as the US mainland, he looked it up, the US is about 100 miles costa to coast larger than Australia.
Along the lines of kippers, scampy isn't a type of fish either, it can be one of several types. And who ever asked, kippers are abit marmite, I love them just with bread and butter.
So we have done Portsmouth, the channel tunnel how about, most of the London underground is above ground and that the lines are at different depths so you could be on a train in a tunnel and underneath there is another train crossing your line but much deeper.
Oh and the 'map' of the underground isn't a map, if you end up at the wrong end of the Northern line at Golders Green you can take a bus to Finchley in about 10 mins, you don't need to go all the way to Camden and swap. One of my Flatmates, who had been living in London for 5+ years, and was moving from one spur of the Norther line had been travelling via Camden for about a week before I told him about the buses.
IDefinitelyHaveFriends Alaska isn't an Island, although it might look like it on your map.