ComputerCraft is a mod that adds lua programming to minecraft
You can use it to control redstone devices
You can also use it to print text to screens that act like programmable signs
Theres also little robots called turtles that you can program to move around or mine for you, they can even build (but its pretty impracticable to have them build, unless its a floor/ceiling)
http://www.minecraftforum.net/topic/892282-124-computercraft-132-updated/Ive only used it for about an hour and ive only made 3 things with it so far (it took me awhile cause i dont know lua, although its very easy to learn when you know another programming language)
The first thing i made was a password protected door
Normally to make a locked door you would need tons of redstone and would have to build a bunch of gates/latches
It looks a lot nicer like this
The display changes depending on if the password was right or not:
You enter the password by interacting with the computer(the block that has >_ on it):
Thats also how you program them (obviously it wont say enter password on it when you first program it)
I didnt put in anything here for failure, but you could easily have it open pistons to drop you into lava if the wrong pass is entered
Now i said easily, but its not really that easy, you do need some programing knowledge to make it work
For example, to make that door, which just opens when you type the correct password in, i had to write this:
Its in picture form because i couldnt copy it from minecraft and i could find where its saved in the minecraft folder
And that is what it looks like in game when your programing, just a text box that you type into (you hit cntrl when you want to save or exit)
The functions that end in "m" (like redm) are for the monitor, the display thats on top of it in the first 3 pics
So you dont actually need those to make the door work, i just added that after i finished it because i wanted to figure out how to use the monitor
I also just threw this together so dont judge the code too harshly
To me typing that is easier then building a series of connected redstone gates to make a locked door
I also made a mining robot, which mines in a 3x3 square donut (leaves the middle block) straight down, it doesnt stop for lava which means that if it goes into lava you pretty much cant get it back without spending a few mins cleaning up the lava
And it doesnt actually stop, it cant mine bedrock, but when it hits bedrock it keeps searching for blocks to mine, even when it ends up surrounded by bedrock it will just spin in circles (since it only ever goes down)
I cant figure out how to detect lava or bedrock, there is a way to compare blocks, but only if the block is in the robots inventory, which doesnt work for bedrock or lava unless you cheat to put that block type in its inventory, and even then thats 2 of 9 spaces taken up (it holds as much as a dispenser
And theres no way for it to empty its inventory into a chest so its kindve crappy for mining even if i did program it better
The third thing i made is a robot that builds by taking commands from a server computer
Im only making that to figure out how the rednet api and wireless modem work, i havent finished it
The one thing i dislike about it is how it handles debug messages
While i was making that passworded door i typed term.clear instead of term.clear()
Instead of saying something like "Line|21|Expected (" it says "178"
Most of the time it will say something like "Line|16|Expected =" or whatever is wrong with that line, but if you forget a "(" or ")"anywhere in the code it only says "178"
It took me 15 mins to realize what was wrong
Overall the mod is great and has a lot of potential
This mod works on serversBut the server has to have it installed
It would be cool if cd/seren put it on the server, but i think that would require everyone that connects to the server to have it
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Subject: ComputerCraft 
