Many, many places. Pretty much where laws, domination, and authority are lacking, anarchy is happening, at least on some level.
If I want to go all anthropologist, I will tell you about informal social bonds and mores. If I want to crimethinc about the situation, I'll tell you everything from potlucks to trainhopping to militant street protests are anarchy. If I want to be pro-insurrectionary, I will talk about any time someone rebels against the system. If I want to give you an egoist perspective, I will focus on how I live my life to my own desires, and fuck you very much!