I have some ideas for minecraft, for the Minedeas contest! My modification to minecraft would give you lots of fun and useful abilities to use in gameplay!
There should be a new ore called Darkstone ore. You need an iron pickaxe to mine it, and when mined, it drops a Darkstone Gem. If you smelt a Darkstone Gem in a furnace, It will give you 2 Shadows. If you craft Shadows in the formation of any piece of armor with at least one Darkstone Gem in any place, you will get the piece of shadow armor. When you a wearing shadow armor, you can jump 2 blocks high, and take 1 and a half less hearts of fall damage.
If you craft Shadows into all of the slots in a crafting table, you get a Shadow block. If you stack 2 Shadow blocks on top of each other, with a jack-o-lantern on top, it will spawn a Shadow golem. Shadow golems are transparent and looks like a dark-colored Iron Golem. He has twice the amount of health, does 2 hearts less damage, and jumps 2 blocks high. He will defend you from all mobs, but he is afraid of ghasts and wolves.
Also, I have one more idea. It's just for fun. If you put bread in a crafting table, it will give you 4 bread crumbs. If you feed them to chickens, they get tamed. Tamed chickens grow a little bit and follow you around.
Thanks!