Hey, I'm developing a challenge mod. With this mod on your Server you can play a lot of Challenges. Everything you need to do is puting the mod and its dependencies in the mods folder of your server.
Commands:
/settings <opens the settings gui>
/timer resume/pause/reset <start or stop the timer>
/reset <resets the worlds>
Challenges:
NoJump (You die if you jump)
BlockRandomMob (When you break a block a random entity will spawn at your location)