Fight Clubs

Violence is a fact of life in Murgulmuir. The degree to which it is tolerated depends on who you are and where you are in the city (see Crime and Punishment for more on this). Brawls, melees and murders are relatively common.
For those who wish a more lawful and civilized way to resolve their disputes there are two Arenas in the Martial Ward specifically for dueling. One is set up for fighting with melee weapons, the other specifically for firearms. Both are supervised by the guard, have healers on hand and charge for right to fight there. It is expensive (usually 5 silver each for the melee arena and 1 gd each for the firing range) but the guarantee that they guard will not interfere can be worth it.
In a place as violent as Murgulmuir there is an insatiable bloodlust that is fed by the city's many Fight Clubs and the audiences who flock to them. The following are only a few of the establishments who trade in spilling blood for the pleasure of cheering crowds -

Bloodforge

Dwarven Ward (Lower Wheel) 
Atmosphere: Raucous /  Admission: 2-6 silver to get in the door depending on the night (double for non dwarves) / Amenities: Beer. Lots and lots of Beer. 
Challenge: Lvls 1-5 / Risk: Brutal / Healers: Sometimes (mercenary services) 
Potential Profit: Modest (at the end of an evening anyone who fought gets 3gd, popular fighters who helped draw a crowd get d20 gd extra)

It may be a cliche that all dwarves love beer and fighting and while it may not be universally true it is true enough that a place like this is the most popular spot in the dwarven ward. Beer is brewed in-house and served in quantities dwarves expect (it is said that what a dwarf considers a mug would be considered a pitcher by humans).
Bloodforge is essentially a three story tavern with balconies that overlook a central area where fights are held (the dwarves call them throwdowns). There is no formal boundary, arena or announcer. Fighters call out opponents and if the opponent accepts they fight. It's tradition to fight shirtless and bare fisted but there aren't any rules. Fights are usually 1 on 1 but big brawls break out every hour or so. Serious injuries are common and there is at least one death every few days.
A massive dwarven woman named Gwizelle runs the place but everyone calls her "the Bride" because she has received so many proposals from those who admire her toughness and skill as a brewer. She fights as shirtless as any man and has covered her breasts with tattoos of husbands she has outlived. The rough and tumble nature of her business is only possibly because she has an agreement with the guard and has explained that if her people don't have an outlet such as that provided by Bloodforge it would be bad for the city. As a concession there is always at least one dwarven guard stationed nearby on every fight night.

The Cellar

Lower Wheel
Atmosphere: Ravenous /  Admission: 4 silver / Amenities: Free food and cheap chunky ale  
Challenge: any / Risk: Minimal / Healers: no
Potential Profit: Modest (the winner of each preliminary match earns 1gd from the house and 2d4-2gd in tips, the Top Cook for the night earns 3gd and 2d8-1 in tips)

Not all battles are fought with weapons. The Cellar is a club that is only open once a week in a literal cellar beneath a warehouse. Each night 4 cooks face off, first paired off in two preliminary matches then the winners face off to determine who will be named "Top Cook" for the night. The "Kitchen Pit" is literally that. Two stations, one on each end. Ingredients are hung from hooks and stacked on a big round table in the middle. The audience watches from the edge of the pit. The Host is a Tiefing who calls themself "The Gurgitator" (Gurge for short). Gurge sometimes tosses new ingredients into the pit mid match to spice things up. One or twice a night the ingredients include creatures in cages hung from the ceiling that can only be reached by climbing a knotted rope. "Cook Fights" where the combatants come to blows over something they want to use that is in limited supply are common and are allowed as long as the cooking continues. Each match is timed using an hourglass Gurge sets on a special shelf where it is backlit by a magical light. For one hour the cooks may prepare whatever they like and when the finish something they put it on trays and set it on the edge of the pit so the audience can consume it - which they always do in a matter of moments. Three Gnome sisters (Deeta, Rita and Princess Poo) serve Ale from big pitchers all night. Winners are decided by applause. At the end of the night everyone who enjoyed the show leaves tips for the sisters in empty pitchers and sets a gold coin on the hourglass ledge for Gurge. There is a regular clientele of foodies from all over the city. Upscale patrons sometimes wear masks (half masks so their mouths are free to eat). It is tradition that the Top Cook and his guests eat for free anywhere in the city. A surprising number of places are aware of the Cellar and keep track of who has won. Winners usually have very little trouble finding work should they need it.

The Pit

The Warrens 
Atmosphere: Primitive /  Admission: None / Amenities: None 
Challenge: Lvls 1-3 / Risk: Brutal / Healers: None 
Potential Profit: Modest (winner takes d6-1 gd/lvl/bout)

Literally a pit sixty feet across sounded by a fence with a gate at each end and a ramp from the gates into the twenty foot flat spot at the bottom. This arena is marked by a ring of 12 wooden poles roughly 4 feet high from which weapons and shield hang from hooks. A match begins with both combatants entering (stripped down to loincloths with no equipment), making their way to the center and pounding fists together. At that point they can fight bare handed or run to the posts to grab some gear. Onlookers can watch from the fence for free. The organizers make their money by taking bets. Fighters are paid a cut of the take. A Hobgoblin named Boris runs the place. His Goblin assistant Damo takes the bets, figured the cut, pays the fighters and distributes the winnings. Those who want to fight talk to Boris. If he has a good match for you, he will put you in.

Shadowcast

Magic Ward (Upper Wheel) 
Atmosphere: Elegant /  Admission: 1gd (10gd VIP) / Amenities: Bottle Service in VIP 
Challenge: Lvls 2-6 / Risk: Moderate / Healers: provided at no cost to participants  
Potential Profit: Excellent (participants get 5gd up front and the winner takes an additional 5gd/lvl)

An arena constructed for two casters to face off against each other. Participants stand atop 5ft square, 15ft tall platforms set 40ft apart. They may not enter with anything other than whatever focus and materials they need. Familiars are only allowed if both combatants agree. When the battle begins they attempt to knock one another out. If a caster is inactive for a 20 count (3 turns) they forfeit. A rune circle protects onlookers from damage. Battles are announced from a hovering platform. An enchantment amplifies the announcers voice so it can be heard easily throughout the stadium. He is also able to trigger a device that dispels all magic within the run circle (it is only intend to be used in emergencies and is thought to have a limited number of uses per day).
Shadowcast is run by the Wanding Academy - a school for BattleMages. The Master is a human mage named Adras the Gray. He encourages his students to practice by taking part in matches in the Shadowcast arena. His regular announcer is a Tiefing Bard who calls himself "Glorious". There are tournaments held twice a year where popular combatants are lured back with much larger purses. These are very well attended and the stadium us often filled to capacity

Twenty One 

Lower Wheel  
Atmosphere: Intense /  Admission: 3 silver (3 gold for Blood Matches, 3 Platinum for Death Matches) / Amenities: Full drink service 
Challenge: Lvls 2-4 / Risk: Moderate / Healers: Yes 
Potential Profit: Modest (make DC 14 Performance test - regular match 3 sp 1 if failed +1/pt, blood 2gd +1/pt, death 5gd +d6gd/pt double total if the loser is killed) 

The name refers to the saying "Two may enter, Only one leaves" (two and one - twenty one). This is a large sturdy stone building that looks a bit like a temple from the outside but resembles an arena one you pass through the iron gates. It is run by a human known only as Gryphon who was once a famous gladiator. When he lost his arm in the ring he spent the fortune he had earned on paying the gnomes of Toc to replace it with a mechanical one. He is often bear chested so he can show off his gryphon tattoo which animates when he fights.
Fighters sign up with Gryhons assistant Mutt, a young dogfolk fellow who has an excellent memory and never forgets a face so never needs to take down a name. When everyone has signed Mutt meets with Gryphon to set the slate for the night. On most nights, fighters get to fight one or twice if they win the first match.
A regular match is over when someone conceded or falls. In a blood match, here is no concession. The battle rages until someone falls. In a death match the victor has the right to kill the loser. The fate of the loser is often decided by consulting the crowd.
Twenty One is a very popular attraction and there is always a lively crowd. Because they serve (overpriced) drinks (by Isa a human barmaid and her staff) when they get rowdy the peace is ensured by Maddox, who was a regular contender and popular favorite until Gryphon hired him to bounce anyone that gets out of line.
Before each fight those that have been matched may decide what armor and weapons will be allowed. Breastplate, Shield and spear are a popular combination.
A catfolk healer named Seemeesh is always on hand and will launch into action as soon as a match ends. He has some spellcasting ability but mostly uses healers kit. He isn't there to cure someone of all wounds, just to make sure the dying are stabilized and can walk away. He can do more but it will cost you (often around 2gp/hp). He has an amulet that allows him to Revivify but will only use it if he is paid 100gd before a match begins (whether or not whoever paid him falls).