Greetings, Hivemind,
My party are mythic heroes, currently disguising themselves as they explore the occupied town of Losthome in The Lands of the Linnorm Kings.
One of the NPCs they are interacting with is an Ulfen warrior who has allied himself to the winter witches - the party have bluffed their way into his confidence, and he has made them the proposition of competing in a series of "pit fights" to entertain the unruly Ulfen and try to endear them to the town's new leadership of Irriseni witches.
My current map of the "pit" is of a massive sandpit underneath wide floor gratings on the main level of the Ulfen warrior's longhouse (think Jabba The Hutt's trap door leading to the Rancor battle in Return of the Jedi). The pit features spiked walls, and several mechanical, spinning pillars that not only support the grating, but also serve as spinning hazards of jagged metal.
The hope here is that these hazards will affect movement and tactics, but that the players will also realize that they could destroy these pillars to bring the grating down - the encounters I have in mind will include challenges emerging above the fight as well, including other NPCs who may recognize the party as intruders.
But what improvements could I make to this encounter to encourage changing positions and force the players to keep on their toes?
NPC warriors with fauchards using Power Attack and Pushing Assault to push the PCs away from (through) the walls and/or into the spinning blades. Or harpoon-crossbows attached to winches.
Also, chain the PCs together in pairs with 1d3x5 feet of chain between them. Maybe put some wires they slide down using the chains?
The PCs & opponents get thrown into the pit without any weapons, but there are several stashed and displayed around the pit. All are fragile, so they will constantly be scrambling to get their dirty mitts on a new weapon.
More pits in the main pit filled with hazards, like swarms of vipers, piranha, spiders, rats, etc., spikes, beartraps, actual bears, lava, caltrops, ball bearings, etc. Maybe narrow cat-walks separate different kinds of pits? Or side-cells that can be opened to reveal monsters and/or other hazards. Or maybe a big glass orb filled with a hazard the guards throw rocks at until it breaks and spills out its hazardous stuff. Slime? Tanglefoot goo? Fiery caltrops? Quicksand? Oil?
Have the crowd throw rotten fruit and vegetables and even worse stuff at the combatants. Fort save or nauseated or sickened. Guards can throw caltrops or ball bearings or oil at the combatants.
And torches in the pit to light it up for the crowds.
Maybe some sections of the walls push together like a trash compactor. Maybe the floor is covered in 1 or 2 feet of water--and something is swimming down there! Bumping into legs, doing bull rushes and trip and grapple checks. Occasionally biting, etc. Maybe mist obscures vision, creates concealment, etc.
Maybe a tower to climb in the middle of the pit with a key on it? Or maybe even a windmill with a key, a shield, a masterwork weapon, and a maximized potion of cure serious wounds.