Featured on reddit (http://redd.it/1aakq0), this is the larger, plastic key.

The lost city of Horobus, from the Minecraft map Pharaoh's Curse 2 - Wrath of Horobus created by Kiwi_as

1000k polygons object available for download.

Proportional Mixup was suggested by Alex Polonsky. The puzzle is a shape-mod of the Mixup Cube. By having rhombicuboctahedron-shaped cubies, the cubies can be proportional like in a regular Rubik's Cube. However, this puzzle also has 45 degrees slice moves, resulting in some weird shapeshifting.

Watch the YouTube video.
Read at the Shapeways Forum.
Read more at the Twisty Puzzles Forum.

Please contact Oskar directly if you are interested in obtaining a fully colored, stickered and assembled sample of this puzzle.

The volume of space removed by the holes is consistent over all 6 surfaces therefore making the dice perfectly balanced. 1.5cm per side.

I am the origional creator of this model, As can be seen here. http://www.planetminecraft.com/project/temple-of-the-moon-827492/ I made this a long time ago, but I think it seems fitting for use in this contest.

A common simple puzzle consisting of six 15 x 15 x 60 mm block pieces. Plans and solution are available via this website: http://homepage.ntlworld.com/bruce.viney/index.html

Also I've made the plans available to download in case anyone wants to modify or create their own. 

Bottom half of paper magnet puzzle. I have not tested this part yet (but I did create and test the previous version, so this should work). Look at the top half for assembly details.
The previous version was not tight enough for my liking so this one is made tighter, and thus might have to be slightly sanded in the shaded blue region on the second picture.

Opposite ends of this die smoothly loft into each other, intersecting with other pairs.

Top Half of 1" diameter Paper Magnet Puzzle (must order with bottom half... if you want both halves). This is called such because it is designed to lock with a magnet and to be opened with paper or something thin. This particular piece has not been built (a previous version was built and tested and worked fine but I wanted to adjust a few things. I haven't made the new version as I have had no requests). I made two tops and two bottoms, using strong and flexible and detail plastics, either worked fine.
To make it according to my design you would want to also order:
4 neodymium magnets which are .060" thick and .250" wide with the magnetic axis through the faces (axial).
Also you would want a cylinder .100" in diameter to fit in the holes. 1 hole is for locking in the two repelling magnets, the other two holes are optional.
With frosted plastic (slightly transparent) you can put in glowing powder in the top half (recommend V10).
Magnets 1 and 2 must be glued in (one in each half) so that they attract each other.
Magnets 3 and 4 must not be glued and they must be inserted so they repel each other.
I have used common 5 minute two part epoxy and I have used super glue. Either appears to work for the pins and magnets. The magnets should be pushed into position while the glue cures for the best adhesion of the glue.
As seen on the first picture this also has a small logo on the inside face (it is small so it can't really be seen in "strong and flexible").
The solution to the puzzle is to use something thin and push magnet 4 back and then slightly rotate the parts and then let the halves come back together and continue rotating until the hook reaches the gap, then pull the halves apart.
Fairly simple, but hard to see at first.

A board game token designed to look similar to the Minecraft spider.

Cube Created in Blender

1 ghost die, for when you feel like you need to do some bustin'.

The seal of the head of the Time Guys. This one is available for free download. If you do, I just want to see what you do with it.

A small model of three books and a round rubber stamp, designed to be used for board games.

1000k polygons object available for download.

Shapeways Image Popper

A large version of the Pentomino ring --- a 3 by 20 Pentomino packing wrapped into a cylinder. This design could be worn as a (very loose) bracelet, but I'd be interested to see other novel uses for it.