Am I embarrassed to report that I spent 90% of my childhood and adolescent leisure-time in the 1950s and early 1960s racing coloured marbles down a slope. Lining them up, for example, behind a crib board on a supported boardgame board, then lifting up the crib board ,,, letting them GO!… and see which rolled furthest on the carpet.
Knock-out competitions.
Leagues.
Endless hour after endless hour. I even named the marbles – split dark blue, thin red, big light blue, spot yellow… … …
I had a ‘Palace Corbie’ published story in 1996 about it… http://weirdmonger.blogspot.com/2007/03/piano-player-has-no-fingers-no-1.html
Last Balcony: Essex Serpents and Pier’s Echo 
http://www.knibbworld.com/campbelldiscuss/messages/1/5290.html?1320003500
FROM ABOVE LINKED THREAD
And when do you think you lost your marbles, Mr Lewis . . . ?
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Indeed, an interesting question, Gary, if one you intended as playfully insulting.
By hook or by crook I couldn’t seem to keep the original set of my marbles in my possession. Gradually they vanished, what with my own kids playing with them, and other factors or storage and house-moving etc.
It’s commnonly known as Marble Entropy. A special form of entropy that differs from that of one’s mind or body: The marbles themselves, at worst, only chip but otherwise stay integral, but the whereabouts of that Marble integrity increasingly becomes a mystery.
My lifetime’s cloud racing is mentioned here in the review of SANGRIA IN THE SANGRAAL by Rhys Hughes:
http://weirdmonger.livejournal.com/211365.html