The title is pretty much the question. I’ve heard this term orally for maybe 2 years. I saw it for the first time in print on another message board about a month ago. Can’t say “redonk” is ubiquitous just yet … but I’m wondering whether it’s part of some very recent pop culture that I may have missed.
I think it’s just people playing around with common words to make them sound funny.
I also hear “recockulous” and “ridicurous”.
Don’t be dickless, Lucy!
True, true. I still wonder if “redonk”/“redonkulous” has appeared in a recent movie, TV show, song, or something like that. Heck, these days, a video game or well-read blog can probably popularize slang.
I’ve been finding over the past 5 years or so that a lot of what looks like “playing with words” actually had been popularized in some form of media. For instance – People. Writing. Sentences. Like. This. – actually came from the Comic Book Guy on The Simpsons (I don’t watch much … I’ll assume that CBG Talks. In. Pauses.).
Perhaps it’s origin is tied in to the phrase “badonkadonk” or “It’s on like Donkey Kong” ?
All I can contribute is that it first appears on Usenet in 1999.
David Spade may have revived its popularity by his repeated use of it on his Show Biz Show.
[Seinfeld]Wait a minute…did you … say … ridicurous?[/js]
It’s also all over www.cuteoverload.com, along with some of my other favorite non-words like 'snorgle", “muzzlepuff” and “pawsitude”.
That annoying little gnome creature from whatever online service uses it. I haven’t heard it otherwise. I hate him.
See, there’s another example right there of the same thing. My hip, young sister-in-law uses this word (or is it “bading-adang-dong?”) to refer to country music, NASCAR, small towns, and rurality in general.
I thought “badonkadonk”/“bading-adang-dong” was a just a play on the sound of a banjo or something, until I heard that it came from a recent hit country song. Of course, the song might have come after the term … probably did, as a matter of fact.
Playing around with “ridiculous” is not new. Albert Alligator, in the long-defunct comic strip Pogo, complained that something was “ree-dickle-wockle.”
But Pogo used that kind of bizarre artificial elaboration for all kinds of words in the dialect of its Okefenokee swamp-critter characters, not just “ridiculous” in particular. Similar phrases I can think of just off the top of my head include “a big political assassifrassination”, “automobobble”, and “dangerest”.
Actually “[URL=http://en.wikipedia.org/wiki/Badonkadonk]badonkadonk” is something completely different.
I’m just too old to keep up, I tell ya! 
The first time I heard it was on the sit-com “How I met your mother”, they said it in at the start of the second session
Yeah! Thats where I heard this for the first time.
muzzlepousche…hehe
Not so completely different - the country song was “Honkytonk Badonkadonk” which may have been referring to a girl’s nice backside while she danced to Honkytonk, but the apparent hipster use of the term comes from the association with that song and making it mean honkytonk. And slang means as slang is used.
I assumed it was because dong is a slang term for dick, like cock is. So similar to how recockulous is used because cock is slang for dick, redonculous is used as well. The ‘g’ gets dropped off, but it’s still there in spirit.
Comic Book Guy got it from comics (surprise!). Imagine the hero struggling so hard that they can only get out one word at a time. Must… fight… off… raygun… effects!! Where… is… Robin? Can’t… reach… button…!
Didn’t Balki on Perfect Strangers have fun with “ridiculous”?