6. I wasn't talking about voice chat, I mostly meant controller support that would simultaneously allow joystick and keyboard support; most GOOD modern games do this. Primary example (if it wasn't a porting disaster): GTA4.
8. Maybe we could label players on probation? If cars have people inside them, maybe have a guy in an orange prison jumpsuit behind the wheel?
10. I meant more server-side stuff. Just take a look at any decent GTA multiplayer server or almost any TF2 server.
10.a. I was thinking more along the lines of "here's what a script may and may not affect"; if anything is out of place about a script, it should be forcibly disabled. I was thinking that this would be dependent on the server operator (defaulting on "you can mod the HUD and map keys, but nothing gameplay-changing), with more extreme server ops, I bet even HUD modding would be off-limits. On the other hand, with lenient ops, I suspect cheating would be par for the course. Flying cars, invincibility, etc.
As for specific games, I have a few ideas.
1. Chicken Racing: A race involving a long, skinny course and two checkpoints, A and B. Each player is spawned either at A or B, and set free upon the course; a player that spawns at A must go to B and then return; a player that spawns at B must go to A and then return. Collisions are allowed, and damage should ideally be on. Can be team-based!
2. Hide and Go Seek: Except that the seekers have highly limited vision (fog?) and the hiders have enhanced vision. A point is only scored on a hider when a collision is made. Can be team-based???
3. Sardines: Based somewhat on the old reverse-hide-and-seek game*, exactly one player (a hider) is tasked with avoiding the other players (seekers), though hiding in and of itself is not necessary; contact between a hider and a seeker turns the seeker into a hider. Hiders gain points by staying away from seekers, though the flow of points slows down and stops depending on the range to the nearest seeker (maybe the hiders have slightly better visibility than the seekers?). Additionally, each hider should be somehow bound to their teammates, preventing hiders from running off...Or maybe there should be an incentive to stick together? Anyway, straggling hiders should probably become seekers or be removed from the game somehow (though there SHOULD be a bigger incentive to just stick together...).
4. Budget Racer: Tournament racing mode. Each player is supplied a miniscule amount of cash and taken to a junkyard, where they scrape together car parts. A time limit is declared, and each player is paired off with an opponent. If a player wins a race, then they are awarded all of their opponent's possessions. If a player looses, then they can enjoy their walk back to the grandstands.
5. About that engine build-off idea: Maybe each action requires a sequence of randomized button presses? Also: Maybe the idea could be extended to entire cars, and the cars raced, with the performance of each car dependent on the number of correct keystrokes?
6. Drift Racing: Drift races, but judged on a COMBINATION of position and points earned during the race, so that even a last-place trophy can be balanced out with amazing drifting. The number of points gained for each section should be dependent on the time taken to get through the section, to prevent anyone from doing donuts in place or repeatedly backtracking to gain more points than a first- or second-place prize.
7. Something physics-based, like that one ski jump game you always see remade into flash games.
8. Something else team-based.
*Long story short, the game begins with exactly one hider and everyone else seeking the hider; if a seeker finds the hider, then they too become a hider, with all hiders staying in the same hiding spot. The game continues until the last seeker finds the hiders.