...Or some attempt thereof.

Definitions

Interstitial arts:
From the online etymology dictionary:
interstice
1603, from L. interstitium "interval," lit. "space between," from inter- "between" + stem of stare "to stand" (see stet).
From the Interstitial Arts Foundation:
What is interstitial art? It is art made in the interstices between genres and categories. It is art that flourishes in the borderlands between different disciplines, mediums, and cultures. It is art that crosses borders, made by artists who refuse to be constrained by category labels.
The IAF also has a number of essays on the interstitial arts. I haven't read 'em all, but I mean to; those I've read so far are fantastic. And... while of course AW is our wonderful beloved home planet, they also have a forum.
Oh and, wikipedia sez:
Interstitial art is a term first coined in the 1990s, and increasingly popularized in the early 2000s, that refers to any work of art whose basic nature falls between, rather than within, the familiar boundaries of accepted genres or media, thus making the work difficult to easily categorize or describe within a single artistic discipline.


Slipstream (from wikipedeia, because it's a good starting point for the conversation, not because I think it needs to be definitional)
... a kind of fantastic or non-realistic fiction that crosses conventional genre boundaries between science fiction/fantasy or mainstream literary fiction. The term slipstream was coined by cyberpunk author Bruce Sterling in an article originally published in SF Eye #5, July 1989. He wrote: "...this is a kind of writing which simply makes you feel very strange; the way that living in the twentieth century makes you feel, if you are a person of a certain sensibility."
...
It is debateble whether "Slipstream" has been subsumed into the [[New Weird] movement, among like-minded authors, or a new label that has been applied to them after the fact.


New Weird (ditto wikipedia)
The New Weird is an avant-garde literary movement or literary genre that began, nascent and unnamed, in the 1990s and culminated in a series of novels and stories published from 2001 to 2005. The writers involved are mostly novelists who are considered to be parts of the horror and/or speculative fiction genres. The author all critics agree on as a "New Weird" writer is China Miéville, who self-describes as such. Other writers who have been variously described as "New Weird" include M. John Harrison, Steph Swainston, and Jeff VanderMeer — although some of these writers are more properly precursors to New Weird.
But here's a definition from the anthology, which I like better (also quoted on the wikipedia page):
New Weird is a type of urban, secondary-world fiction that subverts the romanticized ideas about place found in traditional fantasy, largely by choosing realistic, complex real-world models as the jumping off point for creation of settings that may combine elements of both science fiction and fantasy. New Weird is a type of urban, secondary-world fiction that subverts the romanticized ideas about place found in traditional fantasy, largely by choosing realistic, complex real-world models as the jumping off point for creation of settings that may combine elements of both science fiction and fantasy.


Surrealism (ditto wikipedia, especially because I know far more about surrealist painting than writing...)


Surrealist works feature the element of surprise, unexpected juxtapositions and non sequitur; however many Surrealist artists and writers regard their work as an expression of the philosophical movement first and foremost, with the works being an artifact. Leader André Breton was explicit in his assertion that Surrealism was above all a revolutionary movement.