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1.
When something is really, really ridiculous.

Can be stressed on the "donkey" or on the "dick" depending on the context of the conversation:
Chump 1: That's ridiculous.
Chump 2: No, that's riDONKEYdickulous.

Chump 1: This is so freakin' ridonkulous!
Chump 2: No, it's ridonkeyDICKulous!
by elevenxover December 13, 2008