My fourth creation, I think it came out pretty well. Better than I was expecting.
http://steamcommunity.com/sharedfiles/filedetails/?id=71679715
This is the successor to one of my earliest test chambers, Step by Step.
It's big, and will take quite some of your time to get completed.
Drop by Drop
The successor to Step by Step, it uses a similiar puzzle mechanic which requires quite some logical thinking. The chamber is gigantic, with 3 different layers, each with their own puzzles. A little flinging is needed from time to time too.
Use CTRL-F6 to quick-save and CTRL-F7 to quick-load often! It's easy to loose a cube or portal by fizzler and have to work your way back.
Download link:
http://steamcommunity.com/sharedfiles/f ... d=71685185
Latest effort:
[moved from other thread]
Well, here's my first release. Ever.
There is a bug where the portals don't render correctly on my sister's computer, but they work fine on mine, so just try it out and rate. feedback appereciated. 
http://steamcommunity.com/sharedfiles/f ... d=71658811
PICTURE
This is my fifth test chamber already... so many ideas...
Transformation
This test chamber requires quite some logical thinking to solve. You can switch the mode of the single chamber between 3 different modes, each with their own unique lay-out. Find the correct sequence to portal your way through!
Download link:
http://steamcommunity.com/sharedfiles/f ... d=71807705
Play it and tell me what you think.
Here i got a few maps that are really challenging.
This map involves mind work.
First: Zentosphere
Second: Fantego
Third: Methodante
In future, I hope to only use the in-game editor as a base for which to edit my maps in Hammer. This is down to me still having a bunch of stuff I didn't learn whilst working with Hammer last time.
So enjoy these maps. 
"some people have their ups and downs like an elevator...
.. inside another elevator"
It's really worthy playing, I swear!
I've spend really a lot of time thinking out this map, please, do me a favor, check it out! Hope you'll enjoy it!
http://steamcommunity.com/sharedfiles/f ... d=71935323
The exit is so close and at the same time so far away... You'll have to face 3 circles of puzzles! Everything remains almost the same... Apart from the difficulty, Are you ready to reach the exit at any cost?
Difficulty: from easy to really hard! Remember to use F6!!
P.S. This map is sooo big and has sooo many entities, that I have reached the limit of props. That's why this test chamber is a bit fuscous)
From Russia with love
Fairly hard puzzle around getting your companion cube home.
Made two more maps:
You can fly! You can fly! You can fly!
Flying through the air ...
http://steamcommunity.com/sharedfiles/f ... d=71442342
Chess Chamber
Looks like a chess field. Wanna play?
http://steamcommunity.com/sharedfiles/filedetails/?id=71900917
Fair warning: Until you 'get' it, it will be hard and probably frustrating.
My first is Test_R001_FallingCube
http://steamcommunity.com/sharedfiles/filedetails/?id=71834592
My second one is Test_R002_U-Tube
Description: U-tube should be a simple test. Unfortunately are half of the portal area not available in your dimension.
Link: http://steamcommunity.com/sharedfiles/filedetails/?id=71908044
I like the second one more, but be careful at beginning turrets are waiting for you.
3 new maps.
A typical flinging map
http://steamcommunity.com/sharedfiles/f ... d=71699984
A very new mechanic that I haven't seen in any other maps so far nor in the campaign
http://steamcommunity.com/sharedfiles/f ... d=71843413
This map should just be considered fun. There are 2 solutions to this, one being very straightforward, the other being quite difficult to figure out.
http://steamcommunity.com/sharedfiles/f ... d=71444480
*for the hard solution, no painting on the 2nd half of the map. Have fun
Once more into the breech!
http://steamcommunity.com/sharedfiles/f ... d=71925371
On a related note, I figured out a way to hide connections a little better. You can make a 2x2x1 room that's not connected to your main chamber. Put a cube on a light bridge with a button underneath. Connect the switch in the chamber so it shuts off the light bridge, and the button in the small room to what you want to switch. This removed the blue dotted connection and garuntees you the smaller less intrusive symbols.