Here's a few:
A variation of the Hostage/General game is one player (BOSS
) is the Hostage/General and he has to be escorted from one camp to the other. The other teams objective is to stop this happening. its more fun because the Boss gets to play but still get shot a lot.
On smaller or open fields, have a set amount of empty hoppers or pods in box at the centre of the field. The objective is to get as many pots/hoppers to your base the twist is this. You need two players one is the medic and one is the runner (both in high viz vest) The runner is the only person allowed to get the pots and return them. If shot its the medics job to resurrect him, the medic can never be out, so they will get shot to pieces, so it calls for a brave or stupid person to do it. The rest of the team must keep their runner alive and the oppositions runner dead.
A variation on the above is just to have the medic keeping everyone alive in a normal flag game but he has limited amount of lives.
i'm sure you can adapt these to suit. Have fun but keep it safe.