Redstone creations!

Yeah, i've been looking at a lot of redstone circuitry recently, and some of the things you can make with it are just amazing. Here are a few examples...

• Simple buttons/levers/pressure plates to open doors/alter minecart tracks etc.
• Combination locks
• Working LED screens/displays (such as clocks etc.)
• Traps for mobs, such as landmines etc.
• Even a fully working ALU to make binary calculations!

I've been playing around with it recently, and have almost finished my mob captured alarm system, where basically I have a huge pit, filled with pressure plates, and these link up to a redstone torch inside my house, so if any mobs are in there, it will tell me by being lit up. I'll post pictures later.

What are some of your creations using redstone?

This sends a minecart when I step on the plate, if I get on the minecart that's sent or get off the plate then it sends another minecart to whisk me away to wherever. I'm implementing a simplified version to deliver specified resource chests to me.
http://img232.imageshack.us/img232/1808/onel.png

This sends my minecart back to the start if I miss it, it's pretty useless though because minecarts will stop before they get this far.
http://img294.imageshack.us/img294/65/78069590.png

This allows me to go straight on or back. It's really complicated because I hid all the wiring to make it look cleaner.
http://img704.imageshack.us/img704/9799/25825569.png

Oh my god! That's really good! Now just to optimise it!

Well, I am a newb to redstone, so I am just starting with the really really simply stuff, locking doors and changing tracks! I am starting to make a minecart transit system in my mountain base. So hopefully I'll have the chance to make more elaborate designs.