If all else fails, try becoming an amateur radio enthusiast: In 1990, a multinational expedition of operators spent 16 days on the island.
Bishop Rock 30 miles from England
Regarded by Guinness as the world's smallest island with a building on it, Bishop Rock stands at the end of Britain's Isles of Scilly, where coastal waters give way to the fury of the Atlantic.
In 1847, engineers started building an iron lighthouse there -- and it washed away in a storm. Its extraordinary successor, first lit in 1858, stands to this day.
Reaching Bishop Rock: Visiting the most southwesterly point in Britain is surprisingly easy -- the St. Mary's Boatsmen's Association runs day trips.
But as Martin Hesp notes, even on a "calm" day you're in for serious chop.
Boreray 60 miles off mainland Scotland
Love the Scottish islands, but want something with a little more bite? Head west of the Outer Hebrides, and you'll find the archipelago of St. Kilda, 40 miles into the Atlantic.
It's one of Scotland's five World Heritage sites, with a main island that was abandoned in the 1930s when crops failed. Imagine the surprise of archaeologists when they found that one of the least hospitable islands, Boreray, was occupied in prehistoric times.
Reaching Boreray: Since Boreray comes under the protection of the National Trust for Scotland, you need its permission to visit.
Then? Lots of time and lots of luck -- with a rugged shoreline and savage sea swell, this isn't an island built for landings.
According to one guide, more people have reached the summit of Everest than have landed at Boreray since the National Trust took ownership in 1957.
North Sentinel Island 400 miles from Myanmar
North Sentinel is one of the 572 islands making up the Andaman chain in the Indian Ocean's Bay of Bengal.
It's surrounded by dangerous reefs, but North Sentinel is intimidating because of its inhabitants. The Sentinelese want nothing to do with the modern world and have repeatedly rebuffed attempts to make peaceful contact.
Reaching North Sentinel Island: You're kidding, right? If the above description didn't put you off, this article about a pair of fishermen who strayed onto the island certainly should.
Rockall 270 miles from Ireland
If you think Boreray sounds forbidding, try sailing 187 miles west of it. Rockall is the tip of an extinct volcano reaching 20 meters (about 65 feet) above sea level, in seas with waves recorded as high as 29 meters (95 feet).
In 1955, the British Empire, in its final territorial acquisition, seized Rockall -- allegedly due to fears the Soviets would build a missile battery on it.
Reaching Rockall: In the words of the recently minted Rockall Club, "visiting Rockall is difficult, completely weather dependent and not cheap."