This ludicroëclectic aesthetic (dare I call it a movement?) seems to combine aspects of dadaism, postmodernism, and punk: a mish-mash of cultural (usually pop-cultural) icons and tropes in service of no coherent central meaning other than being, frequently married to a punkish DIY approach. Influence from the "sampling culture" of hip-hop seems probable. The assertion of an "end of irony" made soon after 9/11, while frequently rejected since then, may have in a sense been correct: if everything is ironic (who knew Alanis Morissette was so insightful? Aside from Kevin Smith, who typecast her as the playful, omniscient God in his films), then irony ceases to be a useful concept in itself.
And with the Spongmonkeys advertising Quizno's on TV, if only for a brief moment, and Happa-tai appearing on Jimmy Kimmel Live, it seems like it's making incursions on the mainstream.