Matrix Corner is a club at the Old Grand Castle Station (read background info about it). It occupies the whole cellar system allthough not all rooms are publically accessible. MC's owner is a former hacker and engineer who has worked with holographic projection for almost 35 years before he started working there. When he bought the bar it was not really a nice place to stay so he tried to make it a special experience. He enhanced the whole area with special holographic systems so that he can actually create any kind of furniture, decoration, plants et cetera (even people?) without really placing them there. However this does NOT work like a holodeck in Star Trek since none of the holographic pictures is of real matter. So you can't touch them!
The front room is about the 20x30x3,00 meters although a holographic picture can visually lift the ceiling to any height above that 3 meters. So can the room be visually enlarged. There are three smaller rooms for private parties or meetings aso. However, hidden from this "main lounge" and the "private lounges" there are another 4 rooms. One of them is three quarters of the main lounge the others are smaller. They do have the latest equipement available in computers but there are also plenty of old and even older computers (some date back to the early 70's). It's partly like a museum. These hidden rooms are the hacker's lounges where most of the noted hackers (freelancers as well as CSB-staff among others) have access, exchange knowledge and (most important) hack.
Needless to say MC owns the most realistic, up-to-date interfaces to access graphical networks. MC itself has an on-line representation on the CHAOS network, one of the greatest, widest spread public visual networks that is partly owned by hackers or hacker-friendly "white-hat" companies. If you log-in you can simply access graphical net with your avatar which you can design yourself or buy from some designer or hacker. Some avaters don't look very nice but they have special functions like avoiding collision-detection or hiding from the others (those are mostly done by hackers). Others do look very nice while their owners probably don't (those avatars are mostly done by designers). The cheapest and easiest way to get an own avatar is to become scanned which means that a digital avatar is created from your real body, so you look like you in reality and then you may of course change your clothes or whatever. This is what most people do because they don't like the idea (or simply the expenditure) to maintain two different (visual) identities. Of course any hacker is meant to create it's own avatar as a proof of his skill and programming abilities.
Events in MC usually take place in the virtual location rather than in the real place because the virtual room can be easily extented to fit the crowd and people from all over the world can connect to the virtual MC and visit a concert or whatever they're interested in.
When you enter the real MC you're identity is checked and you automatically noted by the system. So if anybody you know and who is on your personal buddy list connects to the virtual MC you are noted in the real world and offered to access any of the public terminals to either go directly to the virtual reality or just communicate via chat, phone or similar services. It works a litte bit like the old ICQ system.
Because you're identity is checked you don't need any money in MC. Friends of the owner also know that there is a black list to check whether any unwanted subjects tries to get into the place.
The hidden part of MC (which of course also exists on the visual net as a special secured area, highly encrypted and located on secured servers) is often used for great hacker meetings. Not anybody who considers himself a hacker might enter. Based on the hacker codec you are only considered a hacker if you are noted in the community and known by at least five people who have access to Hacker's lounge. Of course you can't enter if you are a famous Black-Hat or only a script-kiddy. A combination of biometric security and passwords used for security.