Don't know if it counts as avant garde or not, but the actors did practically no actual speaking. Just a lot of acting emotions in an apparent storyline that had I no idea of, and lots of people muttering under their breath in Italian and Spanish, neither of which I speak. (This was in the UK). I have no idea WTF it was about. I'm obviously not arty or out there enough to understand these things. 
Weirder still was that at the end, about half the audience gave them a standing ovation, and the other half didn't. I've never seen that before. Hopefully the people still sitting down were also thinking WTF.
Afterwards at the bar, people were talking about how deep and meaningful it was. I just don't get it.