A whole bunch more minigames have been added to the server now.....

ColorMatch: Jump to the color corresponding to the wool color in your inventory!
Spleef: Destroy the floor under your opponents to make them fall and lose!
MineField: Run to the finish without touching the mines!
Jump'n'run: Jump to the finish!
DeadEnd: Don't fall while the blocks are disappearing behind you!
DisIntegration: Don't fall while the floor is disappearing!
LastArcherStanding: Shoot the others with the bow!
SheepFreenzy: Shear as many Sheeps as possible! Attention: Some of them explode.
SimpleSmokeMonster: Avoid the smoke.
SlapFight: Slap the others and make them fall!
ChickenTag Pass the chicken to others or you'll die!

Best to join with at least one other player and try telling others to do /mp join as anyone else can join in during the game. Each mingame lasts for 60seconds, before moving everyone to the next minigame in the list above. Matches are over once all minigames have been cycled through. It's pretty good fun so give it a try and let other players know about it.

Command:
/mp join - joins the game
/mp leave - leaves the game
/mp shop - opens the shop
/mp help - shows help
/mp list - lists all loaded minigames
/mp stats - shows your player statistics
/mp leaderboards [credits/wins] - shows player leaderboards (credits or wins)

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And the other minigame is 2048, which probably a lot easier to explain by trying out the  original game (use the arrow keys)

The minecraft version is a little different to use....
"On the left hand side of the inventory is the play field. The arrows (hopper, carrot, flint, arrow on the borders) can be used to push the wool items to the different sides of the inventory. On the right hand side of the inventory is the score display. "

/2048 - starts the game
/2048 new - resets the game
/2048 stats - shows playerlist of best scores.