Hey there, I've run games with my friends utilising http://www.mineimator.com/ and http://brikwars.com/. I've posted one of them on here: https://www.planetminecraft.com/blog/game-the-battle-of-mill-island/.
Please note that mastery of these rules is not essential to participate, and if you do not wish to actually fight the battles, control can be assigned to someone else.

The contest:

• Each participant will build an army in Mine-Imator.
• They will either stat it up in Brikwars or give me a general idea of what they want and I'll do it.
• After a designated period of time, I'll pick my two favourite armies on here and set them up in a battle.
• The people who designed the armies will then conduct them in brutal violence against each other using Mine-Imator and Brikwars.
• I will render and post the results, and the winner will defend against a new challenger next time.

Army modelling guidelines:

• Don't use too many parts for each model; please no facerigs, as they slow down the program immensely.
• Size in terms of game purposes can be fudged for the sake of coolness, but try to keep creatures within a couple of blocks to their effective size.
• Siege weapons, wizards, monsters, and the like are all allowed!

Statting guidelines:

• Please read the rules or browse the forums for a basic understanding of how the game works, and use this website to quickly design troops: http://westnordost.de/statcard/
• Each army must contain at least 1 hero.
• Armies consist of 150 CP, but each consecutive battle that an army wins, the next opposing army has a further 10 CP (which returns to 150 next time if they win).

Style guidelines:

• A solid theme with some variation within it creates the most interesting armies.
• My choosing of the best forces will be based upon style as much as efficiency,
  so make them look good!
• An army with backstory for it and its heroes, already-done stats, and a small fort to defend if they win, will be much more likely to be chosen.

Have fun, and if you have any questions just ask!