This is the skin I use in Minecraft which I created for myself years ago. It is based on Lina Inverse from the Slayers anime. You can download it and use it yourself if you want.

Dropbox Link

This is an amazing design for a large gate that actually opens and closes and I think you could probably use any kind of material you like for a door but the fence texture makes this very cool. The whole thing is surprisingly compact when you look at the size of the opening and it is reasonably fast as well. It is also a great introduction to triple pistons.

For reference, under the "floor" the controls go 5 bricks deep. The mechanisms could be easily hidden in pillars to either side of the gate.

Youtube Tutorial

Minecraft 1.5.1

A block swapper has great potential for swapping out a crafting table with a plain floor block (doesn't work with chests), or a stair block used in conjunction with an opening floor, or even glowstone for pop-out lighting.

Youtube Tutorial

Minecraft 1.5.1

This is a fantastic flat world for testing redstone builds in Minecraft. This world comes pre-created with a grid set up as pictured in predominately white wool. It is also pre loaded with a nice little contraption by MyLifeInMC, the original creator of this test world. My addition to it is resetting some system parameters so Creative Mode and Cheats are enabled.

Download the zip file.
Extract the folder into your minecraft saves folder.
Usually: C:\Users\[your_name]\AppData\Roaming\.minecraft\saves

Note: An easy way to find your minecraft saves folder is to go into Minecraft then open your options and Texture Packs. Click Open texture pack folder, then go up one level and open the saves folder.

Enjoy!

Dropbox Link

This is a simple circuit that triggers a server command to set the time to morning so you can skip night and always have reasonably bright daylight.

For this circuit you need a command block which can currently only be obtained with the command
/give [playername] 137

You'll want to set the command for the block to
/time set 1000

The redstone from the daylight sensor to the power inversion needs to be exactly the same amount of blocks as shown. If you want to see more sunset you can shorten the length. It is 9 blocks long. If you make it 10 blocks long it will not trip the torch and the command block won't switch on and off.

Of course if you wanted to do this a cooler way you could use a villager. It trips the redstone with a pressure plate on sunset which powers a command block below his little building.

Youtube tutorial

Minecraft 1.5.1

After I posted yesterday I got the simple block extender working in 1.5.1. The ticks in the repeaters need to be just as shown or it won't work properly. This design is normally shown with the redstone extending to the right of the repeators, but I have taken it around the back where it powers into the yellow wool which enables you to build a wall around the pistons completely covering this mechanism.

If you can't see from the pictures it is 1 tick on the first repeater and  3 ticks on the second.

How my restyling works:

How the designs you normally see on youtube look:

Youtube Tutorial

Minecraft 1.5.1

I hunted high and low for a horizontal block extender that did not require redstone parts extended past the second piston and this was the best I could find so far. Many designs on youtube no longer work in 1.5 and I spent hours trying to rework them to come up with a workable solution.

The tutorial for this design was a little quick for me so hopefully these stills give you a better idea of what the tutorial is showing.

Youtube Tutorial

Minecraft 1.5.1

Doorbells can be simple or complex. This is the smallest surface area I could create and still have two chimes both sound with the one button press. Youtube tutorial shows how to hide the doorbell inside a wall as well.

You can also connect this to a T Flip Flop and then to a door control and have the door open after the doorbell has sounded.

Youtube Tutorial

Minecraft 1.5.1 

One of my favourite doors and there are a lot of variations on this design but this is the simplest one I've seen and very compact. The tutorial is very thorough and the redstone at the top can be connected with a T Flip Flop so that you can have a button inside and outside for opening and closing.

Youtube Tutorial

Minecraft 1.5.1 

A T Flip Flop is a great component to add to many other red stone circuits enabling you to turn a button into a switch. It is much more flexible than using a minecraft lever. A common use is to include it in a door design so you can open the door from the inside or outside with a button.

Youtube Tutorial

Minecraft 1.5.1 

A door activated by pressure plates. Can be constructed as a 2x2 door as pictured or build one side only for a 1x2 door if you prefer. Single door is a great one to hide in corners with an intersecting wall.

Single door requires:
2x sticky pistons
2x wool or other blocks
2x pressure plates
11x redstone
1x redstone torch

Youtube Tutorial

Minecraft 1.5.1