Zajia is one of only a handful of venues in Beijing where you are guaranteed interesting events, and as such it is incredibly important to Beijing's experimental scene. They seem to be open to all kinds of performances, music, noise, DJs, VJs, dance, film, visual arts, etc. It may not be high production values, but that's ok, Zajia is the place where artists can try new stuff out, and get some reaction from the public. So if that's what you're into, then you will not be disappointed. And if you don't like the event you can sit in their comfortable bar next door.

Judging by other comments here, it seems like Arong, one of the owners, has a bad reputation, but I have never had any issues with him, he seems really sweet to me! I've been here for quite a few events this year and every time Arong is running around, helping set up, tending the bar, filming the events, he really throws himself heart and soul into making the venue work. I don't know their economics, but many of the events are free, so I guess renting the space out and the bar are the main ways they make money – which is no excuse for fake drinks of course, but I've never had any fakes. In fact it has some pretty good drinks, including some home-made concoctions (there was a bowl of sangria made by an Italian artist last weekend).

When I first went to an event at Zajia, I didn't know anyone there, I was on my own, and I wasn't made to feel unwelcome at all. And now the nights are warm you can sit out on their steps with your drink and watch the life in the hutong pass by. Perfect!

My girlfriend, a friend and I came here to watch the silent movie/live music performance this Friday, which was great. Not that that had much to do with the bar.
I had a German beer that tasted fake for 40 yuan to start things off, an experience which made me decide not to purchase any more beers there. When we asked for a glass of cold water they said they didn't have any, and only sold miniature bottles of water for 10 yuan. This is when I started feeling like a cash cow who'd come to be milked.
During one of the breaks we went outside, we had decided to buy a couple of cans for the next section, admittedly not stellar behaviour when going into a bar, but given the fake overpriced booze it was the decision we had made. My girlfriend left her bag on the steps and we crossed the road to speak to some friends. At this point the owner of the bar comes accross, rifles through her personal possessions, and when my friend politely said "Excuse me, you can't look through somebodies personal possessions like that" he comes accross and says "I don't know what they do in your f-ing country, but in my country you can't bring your own f-ing drinks" as if that justified his invasion of my girlfriends privacy. He then continued to swear and curse at my friend, at which point I had to intervene to prevent a fight.
So if you like ill tempered people with no respect of your privacy, as well as over priced fake drinks then this is the place for you. Otherwise stay well clear and leave the place to rot.