I'll agree that the whole concept can be a little hard to get.
You could say that an avant-garde film was one that instead of bieng portrayed normally, it was performed live-action in someone's living room with an orchestra playing in the back yard. Of course, this would not be practical for our purposes.
There are a few limitations. Whatever film you decide to make, it will still have to be a video file shared across the internet. So you couldn't add any smells, make it fly across the screen, add surround sound (actually, you could - just that 90% of the viewers have cheap stereo computer speakers) or other fancy "extras".
What we need to do is disassociate the term "avant-garde" from "fancy snob films nobody gets" in the minds of the members.
Many of the people here have the types pf movies that they are comfortable with. Action movies for example. A subtle example of an avant-garde action movie would be the original Die Hard film.
"Huh?" I hear you ask. "Die Hard wasn't an avant-garde film!"
Actually, yes it was. If you look at Bruce Willis today, he is almost synonymous with tough action roles and looks perfectly at home carrying guns, jumping away from explosions and driving cars really fast. However, when Die Hard was first released, Bruce was a comedian. He was most famous for his work on the tv series "moonlighting" and most of the advertising for the film (prior to it's opening weekend success) did not show Bruce.
For a film to be avant-garde, it does not have to have a "gimmick" that makes it different, it just needs to be a bit more creative than a normal film.
Smile and say hello to people. It costs you nothing and can brighten their day.