Many people will remember having great fun on a Space Hopper when the inflatable orange balls made their debut in the late 1960s.
With horns for handles, they were like huge rubber satsumas that you simply sat on, and bounced up and down.
Also known as Hoppity Hops, Hop Balls and Kangaroo Balls, they became extremely popular - but actually served no purpose whatsoever.
TV adverts prior to their arrival promised some sort of wonder device that would see the end of cars and bicycles as a means of transport. From now on, you could just sit on your Space Hopper and bounce off to school or race your friends around the block with hardly any physical effort.
Of course they didn't allow you to go faster, or run further than you could on foot.
But you didn't question them, because they looked cool and you had to have one.
For much of the early 70s, children grew very attached to their orange Hoppers, and spent hours bouncing up and down busy roads.
After 10 bounces they were either still in the same spot, had developed a headache, or fell off and grazed their knees.
Some Space Hoppers also occasionally burst - not an easy task unless they were incredibly over-inflated.
School sports days were especially memorable, featuring much looked-forward-to Hopper races.
Kids would straddle the brightly-coloured beasts, grab the handles and tear off across the grass being careful not to lose their lunch while winning the race.
It was a bit like playing It's A Knockout without having to be a minor C-List celebrity.
Original Space Hoppers had evil faces drawn on them - apparently meant to make them look like kangaroos - but they ended up bearing more resemblance to satanic rabbits, enough to give children nightmares for a month.
There were some kids who failed to harbour a desire for a Space Hopper. But sooner or later they were intrigued, whether it was during the 80s or the 90s, and had to sample at least one bounce.
But what exactly was the attraction of sitting on the large, air-filled rubber sacks and bouncing away like a baby?
Putting a finger on the exact reason is difficult, but something as fundamental and basic as going on a Space Hopper doesn't really stand up to analysis.
In essence, people of all ages just found it a hugely entertaining thing to do.
By far the best way to get full enjoyment from these oversized fun bags was to race them - still a popular pastime today, with special Hopper racing packs even available. Happily, for exactly that purpose, the makers fashion their creations in several different colours and emblazon large numbers on the front - perfect for competition hopping.
Of course, the natural habitat of the Hopper is the common or park, where full entertainment can be gained from its rubbery characteristics and ability to support a human frame.
Bringing one of these, instead of a dog-eared tennis ball and bat, to a Sunday afternoon laze-around is still guaranteed to make you the talk of the surrounding area - as long as you take care to avoid nearby picnics during your hopping steeplechases.
Original Space Hoppers can today fetch around £150, with more modern versions like Rupert Bear and Ghostbusters-themed Hoppers proving decidedly cheaper.
Back in the late 1960s and 1970s, the popularity of the Hopper was all down to hitting the right fad button, in the right era, at the right time.
The micro scooter is a good modern example - it "caught on" but the micro bike didn't.
Although not as popular today, the retro Space Hopper is most often seen in its adapted form, specifically to bring hilarious party game action for both the young and old alike.
But many will always fondly remember the time when happiness came in a package marked "giant orange bouncy ball thing with twirly ears", and some might even have an original still lurking in their garage.
The Italian job
It was Italian inventor, Aquilino Cosani, who came up with the basic design behind the Space Hopper.
No modern copyright exists for the general Hopper idea, so plenty of different manufacturers make the ones displayed in toy shops today.
But most are still made in Italy, by Ledraplastic and Ledragomma - Ledraplastic being the company Cosani founded to originally make gym balls. He created the modern-day gymnastic ball in 1963, which was sold primarily in Europe as the Gymnastik, and during the late 60s, invented a jumping ball called Pon Pon for use in play and exercise.
It had a rigid handle for the grip, and Cosani then redesigned and improved the jumping ball during the 80s after starting up a new company, Gymnic.
Called HOP, the new product featured a ball with handle, but this time the handle was realised in a softer vinyl material and moulded in connection with the ball - progress from the point of view of the safety.
From this, the lovable Space Hopper developed. Adult versions, called Oddballs, then arrived, enabling big kids to rekindle their childhood years and make complete fools out of themselves along with their friends.
There are a couple of theories on the spread of the influence of the Space Hopper - one being that they ended up in the UK because the marketing manager of company Mettoy saw children bouncing around on shipping buoys in Italy - which were pretty similar in shape and design.
So Mettoy then set about designing them with their distinctive pear drop shape - but Cosani is still credited with the original orange-ball design.