Fluxus has been associated with humor since its inception. In fact one of the features that differentiates Fluxus from many other art forms is what could be termed, its "fun factor". As has been said elsewhere, "if it isn't fun; it isn't Fluxus". This feature of Fluxus works has sometimes led to the art and artists associated with Fluxus to be dismissed as "not serious". But as every humorist knows very well, humor can also be serious. Fluxus tends to poke fun at the kind of art that takes itself too seriously.
Fluxus humor takes two primary directions. The first, is as mentioned above, that by being deliberately funny, while also being "serious" art, Fluxus draws attention to the absurdities present in the conventional art market. Pointed humor forces us to ask uncomfortable questions about what we assume to be the unquestionable truth. But what makes the truth true? If I release a stone from my hand, I know that it will fall to the ground. But can I be as certain that one work of art is "great" while another is trivial? What makes it great? Is it valuable because it is important, or is it only important because it has market value? Maybe it is more valuable to make silly little toys and play silly little games.
The small scale and intimate (yet disposable) nature of Fluxus art is the other direction that Fluxus humor takes. Art that deliberately refuses to take itself seriously by consisting of brief, sometimes silly, events, or being made from found and discarded objects (trash), or of short and nonsensical sounding poems, demands to be taken seriously while simultaneously refusing to take itself seriously. Here again, humor is used as a tool to point to the absurdities of the generally accepted "reality" accepted as truth by our cultures.
Like a Shakespearean tragic comedy Fluxus makes us laugh so that we won't have to cry. If nothing is sacred, and if nothing is serious --- well that is a very serious state of affairs. N'est pas?