Let me start by saying, yes... I understand the inherent difficulties of making up a Competitive structure for an RPG that is more or less a cooperative game. That's why I am posting it here, in the hopes that y'all can help me figure one out.

Now, on to my weird thought process. One of my players is about to have a baby. Usually, I would do a Poker for Pampers kind of thing where players buy their way in with a box of diapers and have a chance of winning a $25 gift certificate. I thought it would be fun to turn this on its ear a bit and do a Dungeons for Diapers kind of thing with the same sort of entry fee and chance at winning the same aforementioned $25. Which brings me to my conundrum- how to determine a winner?

My initial thoughts: 1) This should happen in its entirety in ONE game session (3 encounters). 2) Pre-generate low level characters for this one night stand. 3) Maybe do a "rescuing a baby from something's clutches" type of scenario (I would welcome story element and encounter element suggestions) 4) Wondering how to keep score to determine an eventual winner? I have thought about simply keeping a running tally of experience points behind the screen, but I think that could prove too subjective and would almost certainly be too much book keeping in game. I've also given thought to purposefully setting the scenario up to be a "last man standing" sort of situation, maybe even having dead characters reanimate and fight for me so they wouldn't get bored waiting for the end.

And this is where I'm sort of stuck in my thought process. Something I think that could be pretty fun, but I want to make sure it comes off well. Thoughts? Opinions? Suggestions? 

One of my DMs once threw us into a PvP arena.  Anyone who went down came back to full health on their next turn unless someone used an action to finish them off, but the one(s) who went down too often started coming back with less health.  The last man standing won a magic item. 

Okay, so this might be a little silly. It prooobably is a little silly. But maybe you could do, like, a House on Haunted Hill kinda thing? So that, along with their pre-gen character stats, every player also gets a Secret Motivation that they need to keep from the other players until the end of the session, that is directly at odds with the end-game of the other players, but at least parallel enough that they benefit from starting the session working together. Even if they will need to turn on each other eventually in order to accomplish their own mission.

So, if you have the A Child is Abducted and the Players Are Hired to Rescue Him plotline, then maybe one character has the baseline "Rescue the child and return him to his parents" motivation that they all go in pretending to have. But another player might secretly have a "Hired by a devil who made a deal with the parents for the soul of that child, needs to get the child to a specific place by midnight where this devil will claim his soul" motivation, and another player might secretly have a good reason to believe the people who hired the group in the first place were doppelgangers and she's supposed to return to kid to people only she has met who swore THEY were his real parents, and a fourth player might be secretly aligned with the entity who took the kid in the first place and is just going along to sabotage the rescue attempt. All those characters benefit from working together until the kid is pulled from the Evil Guy's clutches except one, who could be defeated by the other players in 3-on-1 combat if he starts PvP infighting too soon- but eventually they'll all have to turn on each other to accomplish their individual goals. Players can't just straight-out Insight to figure out motivations of fellow PCs, but they can try to use Insight to detect whether a PC is lying or telling partial truths, and watch each other very carefully to try and puzzle out what their fellow party-members are up to. Maybe they could each also have their own little bit of background knowledge about the dungeon they're going into or the enemies they're likely to face, that they can, if needed, try to use against each other without showing too many of their cards.

It could be fun but it'd probably be kinda difficult to pull off. xD Obviously, whoever's motivations are satisfied in the end is the winner~

Again, it's kinda ridiculous and probably a bit over-complicated but it would honestly be right up my alley. 

Quote from LittleBird >>

Okay, so this might be a little silly. It prooobably is a little silly. But maybe you could do, like, a House on Haunted Hill kinda thing? So that, along with their pre-gen character stats, every player also gets a Secret Motivation that they need to keep from the other players until the end of the session, that is directly at odds with the end-game of the other players, but at least parallel enough that they benefit from starting the session working together. Even if they will need to turn on each other eventually in order to accomplish their own mission.

So, if you have the A Child is Abducted and the Players Are Hired to Rescue Him plotline, then maybe one character has the baseline "Rescue the child and return him to his parents" motivation that they all go in pretending to have. But another player might secretly have a "Hired by a devil who made a deal with the parents for the soul of that child, needs to get the child to a specific place by midnight where this devil will claim his soul" motivation, and another player might secretly have a good reason to believe the people who hired the group in the first place were doppelgangers and she's supposed to return to kid to people only she has met who swore THEY were his real parents, and a fourth player might be secretly aligned with the entity who took the kid in the first place and is just going along to sabotage the rescue attempt. All those characters benefit from working together until the kid is pulled from the Evil Guy's clutches except one, who could be defeated by the other players in 3-on-1 combat if he starts PvP infighting too soon- but eventually they'll all have to turn on each other to accomplish their individual goals. Players can't just straight-out Insight to figure out motivations of fellow PCs, but they can try to use Insight to detect whether a PC is lying or telling partial truths, and watch each other very carefully to try and puzzle out what their fellow party-members are up to. Maybe they could each also have their own little bit of background knowledge about the dungeon they're going into or the enemies they're likely to face, that they can, if needed, try to use against each other without showing too many of their cards.

It could be fun but it'd probably be kinda difficult to pull off. xD Obviously, whoever's motivations are satisfied in the end is the winner~

Again, it's kinda ridiculous and probably a bit over-complicated but it would honestly be right up my alley. 

Quote from LittleBird >>

Okay, so this might be a little silly. It prooobably is a little silly. But maybe you could do, like, a House on Haunted Hill kinda thing? So that, along with their pre-gen character stats, every player also gets a Secret Motivation that they need to keep from the other players until the end of the session, that is directly at odds with the end-game of the other players, but at least parallel enough that they benefit from starting the session working together. Even if they will need to turn on each other eventually in order to accomplish their own mission.

So, if you have the A Child is Abducted and the Players Are Hired to Rescue Him plotline, then maybe one character has the baseline "Rescue the child and return him to his parents" motivation that they all go in pretending to have. But another player might secretly have a "Hired by a devil who made a deal with the parents for the soul of that child, needs to get the child to a specific place by midnight where this devil will claim his soul" motivation, and another player might secretly have a good reason to believe the people who hired the group in the first place were doppelgangers and she's supposed to return to kid to people only she has met who swore THEY were his real parents, and a fourth player might be secretly aligned with the entity who took the kid in the first place and is just going along to sabotage the rescue attempt. All those characters benefit from working together until the kid is pulled from the Evil Guy's clutches except one, who could be defeated by the other players in 3-on-1 combat if he starts PvP infighting too soon- but eventually they'll all have to turn on each other to accomplish their individual goals. Players can't just straight-out Insight to figure out motivations of fellow PCs, but they can try to use Insight to detect whether a PC is lying or telling partial truths, and watch each other very carefully to try and puzzle out what their fellow party-members are up to. Maybe they could each also have their own little bit of background knowledge about the dungeon they're going into or the enemies they're likely to face, that they can, if needed, try to use against each other without showing too many of their cards.

It could be fun but it'd probably be kinda difficult to pull off. xD Obviously, whoever's motivations are satisfied in the end is the winner~

Again, it's kinda ridiculous and probably a bit over-complicated but it would honestly be right up my alley.