Bethesda Game Studios' Todd Howard presented a keynote speech at DICE today. In that speech he screened a sizzle reel of Skyrim content that did not make it to the final product, which came about from something called the "Skyrim Game Jam".
This "Game Jam" allowed Skyrim developers a week to work on whatever creative ideas they had for the game, which resulted in a myriad of impressive and dynamic concepts presented in the reel.
The reel included in-game footage of:
Dragon Mounts
On-Horse Combat
Spears and Flails
House Building
Werebears
A Giant Mudcrab Boss
Flaming Horse Mounts
Dynamic Seasonal Weather and Snow
Vampire Lords (with wings)
Guard AI lighting dark areas
Pitch Black Dungeons
Moving Dungeon Platforms
Physics Bridges
The video was a presentation streamed live by Gamespot and will be available on their youtube channel soon:
http://youtu.be/XW9FHFFORf8?t=40m38s
This content is something Todd Howard said MIGHT be as DLC, it may, or may not so speculation is rife.
It can be said, however, that the content shown in the reel is most certainly impressive and would almost certainly justify a pricey DLC of at least 20 dollars.
Hopefully we see more from Bethesda in the coming months.
There is no reason to believe that the 'jam' ideas will show up in the game or not as DLC -- these were just 'sketches' by the creators, made with no mind for whether they would work in the game as a whole or not. Just because you saw something in there does not mean you should get your hopes up to see it in game (unless you have the PC version, in which case no doubt other people are trying to recreate those teases right now).
Also that video is unavailable, marked as 'private'.