Usually in TF2 a lot of us set up melee only fights, so the fun is not gun, we love optimizing games.
In Battleground 2, we had a "Pokemon" battle, where our leaders would choose one of us in the line battle server and we would fight it out until we were dead. We played a game where our attempt was to capture the enemy team, if you had a bayonet behind someone they had to walk all the way to the prison zone.
We also did do Pokemon in TF2 too.