MC VERSION DETAILS:

I will be starting to post the new things added in the latest updates/snapshots for minecraft on this page.

This Snapshot, Released on september 27 has these features:


■Lighting system overhauled
■Many blocks previously incorrectly lit now interact correctly with lighting now (stairs, slabs, pistons, etc.)
■Several sound tweaks
■Changed Witch texture scale
■More bugfixes & slight tweaks.
■Debug screen shows which chunk the player is in, as well as where in that chunk, next to the X and Z coordinates.

With this update,bugs have appeared:

■Lighting for farmland, stairs, slabs, cobblestone walls, etc. still have errors (Light can leak through the back of stairs with Smooth Lighting on.)
■Cacti does not utilize the smooth lighting effect
■Witches still act as if harmed when hit by their own potions
■Game crashes when trying to join a multiplayer server or a singleplayer world. THIS BUG IS BEING FIXED IN NEXT UPDATE!!!

This release was mostly to fix bugs.

Here are the fixed bugs(or at least slightly fixed :p).

■“Lots of block placement issues with lighting have been fixed, but nether is still sketchy.”(THIS MESSAGE IS STRAIGHT FROM TWITTER'S MINECRAFT PAGE.)
■Performance seems to be much better now.
■Pumpkin emitting stronger light from the wrong face fixed.
■Fixed the witch's texture being weird.
■Partially fixed Nether lag by making the server do some of what used to be the client's work and increasing chunk load time slightly.
■Fixed some lighting bugs related to upside down slabs and stairs and farmland.

New bugs were added through this update, unfortunately.(Never expect perfect minecraft!!!)

■When you load a world created before this version, it'll still have those dark areas related to the lighting bug discussed in last post.
■Creating a new world in 12w39b takes a really long time compared to before.

Due to time issues, i have copied this HUGE LIST OF ADDITIONS to this page.
This text comes from the minecraft wiki.

Note : Very few references are provided here since most of this content has been directly released in weekly snapshots 12w32a–12w39b.

Modding/Code:
■F3+P will toggle the auto-pause when the window loses focus.
■F3+H will toggle detailed item descriptions.
■Fire spread will be affected by the difficulty.
■Modding API - Will be called "plugins".
■Rewriting Lighting engine. (Y A Y ! ! ! Darkfox is really annoyed at the current engine ) Current engine has some bugs. (See Bug Fixes below.)

Commands:
■Added a Command Block that that can run server commands when triggered by redstone, intended for adventure maps.(Plague should like this!)
■No crafting recipe, only obtainable through /give .
■Use @p to address the nearest player, @a for all players (where applicable) and @r for a random player.
■Only OPs can create it in multiplayer if there isn't already one in the game.
■Will operate in "silent mode" so it doesn't display commands in the chat window.
■Added a few commands for use with the redstone command block:

■/difficulty to change game difficulty.
■/difficulty 0 = peaceful
■/difficulty 1 = easy
■/difficulty 2 = normal
■/difficulty 3 = hard
■Toggling PvP.
■/spawnpoint to change spawnpoint per player (not the actual spawnpoint but more like an invisible bed) .
■/spawnpoint <player> <x> <y> <z>
■/gamerule <gamerule> <true/false>
■/gamerule doFireTick to change if the fire should spread.
■/gamerule doMobLoot to change if mobs should drop items.
■/gamerule doMobSpawning to change if mobs should naturally spawn.
■/gamerule doTileDrops to change if blocks should have drops (does not work for paintings).
■/gamerule keepInventory to change if you should keep your items in your inventory if you die.
■/gamerule mobGriefing to change if creepers and endermen should be able to change blocks.
■/weather [clear | rain | thunder] <time> to change the weather.
■/help command improved.


General/unsorted:
■Improved superflat spawning options.
■Entities (such as Cows, Minecarts & Ghasts) will be able to travel through Nether Portals and End Portals.
■Entities will pass through instantly, but at a longer "cooldown".
■There are no restrictions, any entity at all can travel through the portals.
■Will allow fire burning entities like blazes to leave the nether and potentially burn things.
■Portals will teleport an Entity relative to where it entered.

■Added Wooden Button.
■Can be activated by Arrows.

■Added new potions:

■Night Vision potion.
■Invisibility potion.
■Now hides the nametag. (Sounds fun!!!!)
■Mobs do not see you until you bump into them.
■Turns mobs invisible too. (Invisible creeper,FTW!!!!!)


■Improved villages and villagers to make them more self-aware.
■You can now restore a desolate village or create a completely new village.

■Added a Beacon block block. (refered in-game as "Work in progress" prior to 12w36a).
■Can be right-clicked to reveal a GUI.
■Glows as bright as glowstone and casts a white light into the sky when on an assembled pyramid.
■a 3x3 platform out of iron, gold, diamond and/or emerald blocks is the minimum size.
■additional layers with increasing size under that increase the reach of the effects.
■Each layer unlocks a new level of effects and increases the block's range by 8 blocks.
■You do not have to use only one block type for the pyramid, images have been released by members of the community showing multiple materials in one layer.

■The minimum range is 16 blocks.
■Players within the blocks' range will be given the selected effects every 4 seconds.
■Changing a block's selection costs 1 emerald, diamond, gold ingot or iron ingot.
■Each block can only apply one effect at a time. If there are 4 complete layers of blocks, players can additionally choose between Regeneration or tier II of the previously chosen effect.
■Unlocked effects for each layer of blocks:
■1: Speed and Haste.
■2: Resistance and Jump Boost.
■3: Strength.
■4: Regeneration and tier II of the other chosen effect.



Mob-related:
■Chickens will be fed seeds to breed instead of wheat.
■Pigs will be bred with carrots.
■Carrots used to control pigs. (Interesting L O L)
■a Carrot with a Fishing Rod will be the crafting recipe.
■The pigs start slow but end up going about 5 blocks per second.

■Pigs with Saddles will now drop the saddle when killed.
■Sheep spawn egg can now spawn colored sheep.

■At least four new mobs!
■Wither Boss Mob.
■Wither Skeleton Nether Mob.
■Wither Jockeys.(W O O T! ! !)
■Witch!
■Spawn Egg is included for witch,
■Bat!
■Spawn Egg is included for bat.


■Zombies can now pick up and equip items on the ground.
■Items that are picked up will have a 100% chance of dropping after dying.

■Zombies infect villagers now.
■The villager is immediately turned into a zombie.
■On Normal difficulty, there is a 50% chance of infection and on Hard difficulty there is a 100% chance of infection.
■Infected baby villagers turn into baby zombies.
■Baby zombies are 50% faster, don't age and don't burn up in the sun.

■Infected villagers will turn in to villagers again if you throw a Splash Potion of Weakness at them and right click on them with a normal golden apple.

■Added armor and weapon support for mobs.

■Skeletons and zombies now rarely carry and drop armor of all kinds, sometimes enchanted
■Monsters wearing headgear do not burn up in sunlight.
■Even baby zombies can wear armor.

■Zombies now sometimes carry and drop swords or axes of all kinds, sometimes enchanted.
■Skeletons now sometimes carry enchanted bows, but only on Normal and Hard difficulties, with higher chances on Hard.
■Zombies and skeletons now only drop gear when they're wearing it, and even then its only a small chance of it getting dropped.

■Villagers can now like and dislike you.
■Villagers who dislike you will refuse to trade.
■Villagers will dislike you more for killing their friends or allowing them to die.
■Depending on how much villagers like you, they will start to offer you better trades.
■Trades may be made permanent again or last shorter/longer.


Decoration:
■Added Item Frames that allow you to display an item on the side of a block in a frame.
■Any item can be placed in the frame.
■Some items have special abilities while inside the frame:
■A map in the Item Frame will display actual topographical features.
■A compass in the Item Frame will actually show direction.
■A clock in the Item Frame will actually show the time.


■Added flower pots.
Saplings, Mushrooms, Flowers, Cactus, and Grass (includes Ferns and Shrubs) can be placed in a Flower Pot.

■Added Cobblestone Walls and a mossy variant.
■The ability to dye leather armor different colors.
■16,777,216 potential colors.
■Put dyes and armor in the crafting grid to apply different dyes.
■Item tooltip will then display "Dyed" in the right color.
■Use a cauldron to wash the dye off of the armor.

■Wolf collars will be dyable.
■Added Corner Stairs.
■Added new Map functionality.
■Maps will be clonable and sharable.
■Are now crafted as a close zoom scale and can be extended (zoomed out) by adding more paper.

■Paintings no longer drop when clicking in creative.
■Trapdoors can now be placed at the top or bottom of a block.
■Possibly Lecterns for book display and storage.
■Mob heads, including Creeper, Zombie, Steve, Skeleton, and Wither Skeleton heads. Can be placed decoratively in 16 different orientations.

Foods:
■Added Carrots, Potatoes, Baked Potato, Pumpkin Pie, Poisonous Potato, and Golden Carrot.
■Carrots and potatoes can now be found either in villages or growing in jungle biomes.


Bug fixes
■Fix for "black areas" darkening random spots of maps for no apparent reason.


This took forever to copy as i needed to delete all the source links and other stuff, and correct grammar.
This looks like a great update!!!

cool lol...your really bored arnt you lol

Yep.

At least it's helpful!!!

■Added Swamp Hut structures, for Witches to spawn in!
■Added superflat preset "Redstone Ready" with a 52 layers of sandstone, 3 layers of stone, and 1 layer of bedrock.
■Flatworld configuration now allows you to generate trees, strongholds etc.
■Now pumpkins, tall grass, flowers, trees, mineshafts, dungeons, strongholds, lakes, desert wells, ravines and ores will spawn on superflat maps.

■Custom Item naming NBT tags (intended for custom map makers).
■Using the NBT, it is possible to add custom names to items, as well as a lore list for that item.

■Better inventory management
■The pick block action now works on blocks that are represented as items in the inventory. (Eg: Repeaters, redstone dust, tripwire).
■Pressing the 1-9 hotkeys while hovering over an item will put that item into the inventory bar.
■In creative mode, you can now shift-click items from the hotbar to the survival inventory screen.

■The left-click action will no longer open doors, pull levers, push buttons or open trapdoors. Use the right mouse button!
■Firespread has been slightly nerfed again to prevent infinitely spreading fires.
■Beacon Texture altered, as well as the beam.
■Eye of Ender can now be used in superflat worlds. (only if stronghold generation is enabled).
■Slimes now spawn in Swamp biomes at low light level.