For a while now, I've been working on setting up a server for someone and making coding minigame plugins. The server was finally opened yesterday, and I'm satisfied with the work I did.
The server has one main minigame, Infection. This is a simple game where there are two teams; the infected, zombies, and the humans. The infected have to try infecting the humans, putting the humans on the zombie side. The humans have ranged guns, with no melee, whereas zombies merely are super powerful but on melee. This creates an interesting combination, where the humans have to shoot the infected before they can get near enough the infect.
The humans can use three guns; a shotgun, which is really bad accuracy (only usable at less then 5 blocks range) and a high recharge time (meaning you only get one shot) but can kill zombies in one hit, a sniper rifle which can kill zombies immediately if you get a headshot, and a machine gun which fires tons of arrows at once with no recharge, but low accuracy/power.
Infection is probably the largest plugin I've worked on, but not the first minigame. The first minigame plugin is called Banana Tag. In real life, Banana Tag is a game where all players can tag each other. Once tagged, the player has to crouch down, meaning he/she cannot move. To become untagged, the player who tagged them must be tagged or they can try tagging someone who gets near them. I used the basic mechanics and put them into a Minecraft minigame. To tag a player, you need to hit them twice. Once tagged, they sit down on the ground and cannot get up. The winner is the player who has tagged every player.