Recently, I warped to /warp games and saw that there were 2 signs, both next to TNT Run. There was a sign that had said "What Minigame would you like here?" and I'd like to give a few suggestions if I may. :3
My first suggestion would be a sort of Prop Hunt (For those who play Gmod), where you could go running around, trying to find a spot to hide while the seeker waits in a cage or something. To hide from the seeker, I was thinking to give the player a sort of /md command, except you could turn into blocks.
My second suggestion would be a survival type of Minigame, where you'd have to survive waves of zombies (or other mob), and the last one alive wins (Almost like the Survival mode in GTA V).
Thanks for considering these ideas! ^.^
*Sorry for the long post, here's a potato.