One approach might be look at a lot of what current art is, and look for games that are analogous. Basically a lot of today's art is about being weird, about doing stuff that hasn't been done before and that's not at all mainstream.
Thinking from there, I reckon
IdleRPG is art. It totally turns the RPG genre on its head, and indeed gaming in general - in other games you win by doing something, in IdleRPG you win by doing
nothing. It seems at least as deserving of being called art as 4'33" or a solid black painting.