Reading the sports pages of Metro this morning, I noticed a stray reference to “crimbo”, meaning "Christmas". Crimbo! This word, which must have seemed cheerful, irreverent and rather modern at one point, today feels rather dated – to me, it is somehow redolent of the 1980s, although the OED has a citation for “Dick Crimbo” (meaning St Nicholas) as early as the 1960s. An OED citation for a closely-related word, “crimble”, perfectly captures the period flavour: “Stevie's determined to have a well-wacky Crimble do” (Just 17, 1987).
At any rate, both “crimbo” and “crimble” (the jury is out on whether to capitalise them, although Christmas is almost always capitalised, presumably because of the reference to Christ) seem to be fading from popular use. Over the last five years, there has been a steady decline in their use by British journalists, as the chart below demonstrates.
The earliest citation for "crimble" is in a Beatles Christmas message, cited in the New Musical Express in December 1963: "Garry Crimble to you, Garry Crimble to you, Garry Bable, Dear Christmas, Happy Birthday, me too!"
The earliest recorded reference to "crimbo" is from The Strand Magazine in 1928: "You've saved your man, by crimbo". It's not clear that this is actually a reference to Christmas - to me it sounds more like an exclamation along the lines of "by Jingo!". That said, "Christmas" (in phrases like "Oh, Christmas" or "Jiminy Christmas") was also used as an interjection in the late nineteenth and early twentieth centuries - perhaps, like "cripes" or "crikey", a euphemism for "Christ" - so "crimbo" could be a variation on that.
"Yule" is much easier. It's straight from the Vikings* via Old English, and still survives in Scandinavia in the form of jul and jultid (Christmas and Christmastime), although in Britain it is now mostly used for rhyming or punning purposes in headlines ("Yule duel rage", "uncool Yule rules", "Yule feel fabulous" are recent examples) and phrases like "Yule log". It is also used by pagans to refer to the winter solstice.
* Or possibly the Angles and Saxons; the OED describes its origins as "Teutonic".