SEVEN DAYS A WEEK
PROVE YOUR METTLE
EARN FABULOUS PRIZES
ENTERTAIN THE CROWD
INQUIRE AT THE ARENA OF KORD
NO ENTRY FEE
In the interest of providing a surfeit of options, I recently introduced an arena combat option into my Open Gaming Table. This is one aspect of the OGT concept taken to an extreme.
You see, one of my intents with OGT has been niche-filling. There were several DMs in Buffalo Gamer's Society and Buffalo State CRAGG who were running regular campaigns, and most of them (I've heard) were fairly heavy on roleplay, light on combat. That's normally what I prefer (though 3.5 combat is so much easier to run than the system I played for years that I tend to unintentionally skew towards combat when running 3.5, no matter how much I would prefer RP), but the market is currently saturated on that style of DMing, so I offer a more mindless sort of entertainment.
And the one true weakness of the OGT is how little it encourages roleplaying. A different group each week means there's scant opportunity to really get into a sense of who your fellow characters are. (Though there is opportunity to get, say, a couple paladins thrown into a group together with a couple Chaotic Evil characters, making one of the many possible options "PvP combat", though that's its own little world separate from both regular combat and regular RP.)
So, the relevance of the gladiatorial combat: mindless violence, not even in pursuit of any goal (aside from the cash prizes).
I think there's three kinds of player with regards to this sort of pure-combat thing:
1.) The kind of player whose favourite part of D&D is the tactical combat. This kind of player would do better to play 4e, where they've slightly polished the combat and stripped out everything else, but in the absence of a 4e game, they're likely to find this 3.5e gladiatorial combat satisfactory.
2.) The kind of player whose favourite part of D&D is getting more powerful. This kind of player is likely to love this gladiatorial combat, because it comes with more consistent and faster rewards in terms of XP and treasure. If you go exploring or just RPing, you'll get roleplaying and exploration experience, and you're likely to come across some monsters, though not all those monsters are likely to have treasure (especially in the lowest-level option of my OGT, the mine infested with mostly centipedes). If you sign up for gladiatorial combat, you're faced with a chain of monsters with very little in between, and a cash reward after each match.
3.) The kind of player whose favourite part of D&D is roleplaying or achieving in-game things or really just about anything else.
The nice thing about the gladiatorial combat in the Open Gaming Table is that you don't have to do it. If mindless fighting or repetitive grinding is your thing, you can pick this one option and keep with it until it's no longer challenging. If neither is your cup of tea, well, one player can pretty much veto any option if they object strongly enough.
I seem to recall coming across at least one prestige class somewhere which was centered around gladiatorial combat, oriented not so much towards beating your opponents as towards being entertaining while doing so. So consider encouraging your players to make Perform checks as they fight (probably associated with whatever violence-related actions they're taking, rather than making them waste standard actions on making the check), and maybe they'll get a bonus, because as far as the event's organizers are concerned, entertaining the crowd is the very point of the exercise.
My players should stop reading here.
So, design philosophy on setting up gladiatorial combat. I took as my model, of all things, Who Wants To Be A Millionaire.
There are eight rounds. Each round has an encounter level equal to the number of the round (e.g., round 1 is a CR1 foe, or two CR1/2 foes, or three CR1/3 foes, et cetera). This was largely arbitrary; you could easily have more or fewer rounds, or associate each round with a higher or lower encounter level. In my "NPCs above level 5 are super-rare" world, I set the upper limit at 8 mostly because that's about the strongest creature a huge group of NPCs could conceivably handle.
After each round, you have the option of either taking your winnings and going home, or gambling everything you've won so far on the hope of getting even greater winnings next round. (There's few enough rounds that I didn't bother with including rounds where you can bank your winnings and go home with at least that much if you lose later on.)
Reward-wise, it needs to always be in the party's interest to go on. If you can get more or equal money by taking your reward and then starting again at round 1, then you're likely to do that. So each round's reward needs to be more than twice the previous round.
For the early rounds, at least, the reward should be less than the average recommended treasure for having beaten encounters of that level. e.g., the reward for round 3 should be less than what you'd get if you went out into the wild and defeated a CR1 creature, a CR2 creature, and a CR3 creature. The increased reliability of the gladiatorial combat should come with a decreased payoff, just so it's not always the obvious best option. (Whenever there is a choice, if there is an obvious best option, then it's not actually a choice at all, but rather a decision or calculation.)
The later rounds can be a higher payoff than this (e.g., it's okay for round 8 to give you more money than defeating a CR8+CR7+CR6+CR5+CR4+CR3+CR2+CR1 creature would), for various reasons, including: you'd have to start incredibly small to also adhere to the "more than double each round" rule; by that time the players are probably getting a little fatigued by such constant combat; increased risk (you stand to lose not just the treasure for the current encounter, but the treasure for the 7 previous encounters, too); and at least one more reasons which may become clear when I bring up the possibility of PC-on-PC combat in round 4+.
The numbers I came up with, based on the above principles:
Round : Treasure Value for Equivalent Monsters : Arena Payoff
1 : 300 : 80
2 : 900 : 200
3 : 1,800 : 500
4 : 3,000 : 1,200
5 : 4,600 : 3,200
6 : 6,600 : 8,000
7 : 9,200 : 20,000
8 : 12,600 : 50,000
In each round, foes of appropriate level are determined from a predetermined table of what the arena guys are likely to have on hand.
I've also added a bounty issued by the Church of Kord for any rare and unusual creatures, to be used as arena foes; if the PCs bring back anything that's not on the list, it'll be added. It also occurs to me now that I should decrease the probability of each foe after it's faced, but only if the gladiators kill it - the Church doesn't have an infinite number of each creature on hand, after all. Dynamic lists are fun!
At round 4, I introduce the possibility of making half the PCs fight the other half of the PCs. At round 5, I introduce the possibility of a PC free-for-all, every man for himself. These possibilities remain until the last round, but they're never particularly likely. Only the PCs who are victorious in this round get to go on and collect more winnings in subsequent rounds. This is potentially problematic, but I foresee "Crap, the party's strength is halved/4thed/5thed/6thed, let's just take our winnings and go, we won't be able to beat the next round". If half the party does decide to go on, I'll probably let their players play the monsters, let them try to get revenge on the players that beat them. This portion of the idea has not been really thoroughly thought out, but it's the kind of thing I'd rather refine after playtesting.
In each round, to switch it up a bit and make it exciting, I also set conditions or restrictions for the PCs. My current list is as follows:
No magic (including magic weapons and magic items)
No weapons or magic (unarmed strikes only)
Ranged attacks/spells only
Melee attacks/spells only
To first blood (a participant is defeated if they take any damage at all; this is super-easy)
PCs are chained together in pairs (must remain within 5' of one another)
PCs are all chained together in a line
PCs are blindfolded.
Ring match (a 30' radius circle is drawn in the center of the arena; if any participant crosses the line, they are defeated)
PCs have one arm tied behind their backs
Arena is flooded 6" deep with water (difficult terrain)
PCs are chained in place and cannot move
More foes enter the arena each round; you only need to survive for 5 rounds (I anticipate this will be super-hard).
The "chained together" options are only really workable if you're using a group initiative system.
If you can think of any more fight conditions I could add (note that this is distinct from foes to fight, which are a different list entirely), let me know in the comments. I don't consider this list complete, it wants more entries.