I got 4 good games
GAME 1
Name of game variant: Team Leader
Optimum number of players: between 3-4 on each team
Field type: Just an open field with a couple of bunkers on each side.
Rules: Each leader wears an orange vest or something to identify them. All players have guns. The object of the game is to shoot and hit the enemy leader. If your leader is alive, you can get hit as many times as you want without getting out, unless you plead mercy from getting hit too much

. Once your leader has been hit, your infinite hits on your body is gone, and next time you're hit, you're out.
And any other important stuff you can think of: Try to make a rule with you and your friends that doesnt just have the leader sit in one spot the whole time.
GAME 2
Name of game variant: Dare-Devil Capture the Flag
Optimum number of players: 4 on each team.
Field type: Just an open field with a couple of bunkers on each side, and just a little cover in between each base
Rules: Normally in capture the flag, the flags go on the respective team's side. Not this time. The flags are placed right next to each-other, in between the bases. The little cover that is in the middle of the field is your only cover while trying to get the flag. There are 2 ways to win:
1: Your entire team gets out (To get out, you simply need to be hit once)
2: You capture the other teams flag
Other important things: MAKE SURE THERE IS SUFFICIENT COVER IN THE MIDDLE, otherwise, getting the flag will be near impossible.
GAME 3
Name of game variant: Limited-Ammo Elimination
Optimum number of players: 3-4 on each team.
Field type: Just an open field with a couple of bunkers on each side, and just a little cover in between each base
Rules: Normally in a paintball match, if you run out of paintballs, you can re-fill. Not this time. Each person fills up their hopper to the max (or if you want to be fair, each person gets roughly 100 paintballs in their hopper). The challenge is to make your bullets accurate, and lasting. If you run out of ammo, you're out. If you're hit, you're out.
Other important things: Not much.
GAME 4
Name of game variant: Doubles
Optimum number of players: 4 teams of 2
Field type: Just an open field with a few bunkers and other cover spread out.
Rules: Each team starts at a different point in the field. All it is is that you have one partner, and your objective is to eliminate all the other teams. The challenge is that you can be fighting one team, then suddenly another team flanks you and pwn's you when you aren't even paying attention.
Other important things: Teamwork. You and your partner need to communicate in order for success.