"Stamp collecting dispels boredom, enlarges our vision, broadens our knowledge, makes us better citizens and in innumerable ways, enriches our lives," said America's President Roosevelt.
Undoubtedly philately, to give it its official name, is a popular hobby enjoyed by millions. Most people have some sort of hobby, from gardening to golf, pottery to paragliding and tatting to tai chi.
But what are the world's most unusual hobbies?
Before landing the title role in the hit British television series Doctor Who in 1987, Sylvester McCoy was well known for his many unusual hobbies. Adept at playing both the xylophone and the spoons, McCoy also juggled and, on occasion, stuffed live ferrets down his trousers.
Most of us enjoy some sort of hobby - but few as wacky as McCoy's.
However, there are plenty of folk out there who have a pretty bizarre taste when it comes to their recreational pastimes.
Take the American who admits to collecting golf balls. Not any old golf balls - just the white ones with brand logos on them.
He writes on the web: "I have about 300 - a tiny, tiny collection - golf balls with logos on them. The logos are of different golf courses, companies, and events. I reject dirty balls and balls that aren't white (like the hideous orange or yellow ones).
"I trade non-logo golf balls for ones with logos - people aren't usually terribly interested in keeping them - and I find logo balls in hazards, under bushes, and so on. I don't have any duplicates (that I know of). It'd be nifty if I could find some software that would store pictures and information about my collection, but it's mostly 'something to do' when I do it."
Then there are the anoraks who collect those laminated safety cards from airplane seat pockets which the flight attendants always ask passengers to check over before lift-off. These are apparently collected and traded enthusiastically in some quarters, with the cards from obscure airlines being the most prized. Other demented souls collect the sick bags - which makes beer mat collectors seem sophisticated.
One of the fastest growing hobbies in the USA is said to be roasting your own coffee beans, though why anyone should want to bother when ready-roasted beans are easy to come by is anybody's guess.
We've all heard of people who go caving as a hobby. Geologists and recreational explorers gear up with headlamps and ropes and head for the nearest lava tube and courageous scuba divers explore the deep to map new sea caves and discover strange creatures of the dark.
There is another, lesser-known form of caving that has become a rather unusual hobby for some. It is urban caving - sometimes called draining - a form of urban exploration that involves crawling through man-made caves.
Urban cavers are often unauthorised explorers. They may target drainpipes, grain elevators, missile silos, manufacturing facilities or the attic in your house. Man-made tunnels are a favourite destination. Urban cavers investigate abandoned tunnels such as mines, headraces, tailraces and rail tunnels.
They also poke around in active steam, power, telephone, and water tunnels, as well as subways and storm sewers. Institutions such as universities, hospitals and asylums are popular spots for urban explorers.
Quite what they are hoping to find remains an enigma. But if you are interested in urban caving, you are advised to take a few precautions before you start draining. First, check to see if exploration is legal in that area. Next, check the weather and don't go draining when it's raining or when it might rain. Drainage pipes can fill without warning.
There are also unusual hobbies like dumpster diving, which requires participants to sift through rubbish bins and skips for useful objects and treasures other people have thrown away.
Doesn't all that make your favourite spare time occupation of watching telly sound just a tad dull?