|Inside Bizmo's Brawlpub.
Secondly, anyone can enter the pub and watch. However, to compete you need to be a member and this requires acquiring a Blood-Soaked Invitation. The fights/brawls are between a player (real-life person) and an NPC - not PvP. There is also a queueing system and only one person can fight at a time. One guildie has already moaned at this system and has said phasing would be better in order to allow several fights at once. I, however, support the system from a spectator's viewpoint - I like to watch the terrible just as much as the brilliant! I also wouldn't like to have to choose who to watch simply because you could miss something spectacular.
So, the Blood-Soaked Invitations. These can be bought from the Black Market Auction House (BMAH). On my server (Dragonblight - EU) they have been selling for anything up to around 30K. Alternatively, they can also be obtained from killing rares within Pandaria. My boyf and a fellow guildie managed to get one from killing Horde Champions at Domination Point. Hordie's can obtain them from killing Alliance Champions at Lion's Landing. (Euphyley has written a great blog about these Champions here).
Once you have your invitation and use it you get The First Rule of Brawler's Guild. You are now able to queue for fights and this is done by talking to a guard. The idea is to progress up through the ranks, with the opponents getting harder each time. There seems to be a number of guides springing up on YouTube etc. Reaching Rank 7 results in the achieve The Second Rule of Brawler's Guild which awards one Brawler's Pass. This pass is tradeable and can therefore be given or sold to someone. I've been reading about and it seems that one pass can be obtained per character and given that the initial invitation is account-wide you could level a number of characters up through the ranks to get these passes. This means that the number of people able to fight will grow exponentially.
As mentioned earlier, my boyf and a guildie managed to obtain an invitation from a Horde Champion. As my boyf is quite busy with work over the pre-Christmas period our fellow guildie took it, with the idea that he will give his first Brawler's Pass to my boyf. He has been working his way up through the ranks (I'm not sure what rank he is currently) and I went to watch him fight earlier in the week.
Generally, I think that the Brawler's Guild offers an excellent spectator sport within WoW. I realise that this seems quite stupid, considering it's essentially paying money (your subscription) to do nothing and watch others. Nonetheless, I really enjoy watching people fight. You get a whole range of people, from those who take 10seconds to kill a boss right through to those who die in 5seconds but just won't give up and queue again & again to die some more. So, if you haven't yet popped in and had a look a really do recommend it!
Update: I've now visited the Horde version - located in Orgrimmar (Valley of Honor, north-eastern building) and personally I think its more what I had imagined than the Alliance version.