http://vimeo.com/31136828

There is the video.

I guess it depends where you are applying to.
But if you're going to talk about the body and the city, maybe this will help-

http://www.amazon.com/Skateboarding-Space-City-Architecture-Body/dp/1859734936

Thanks for the info!

I'm working on a residence with a  swimming pool which is designed by California Skateboard which when empty is designed for skate boarding.  Everything from the curves of the pool  to the the finish hardened liner coat to the pool coping.  The owner  has a passion about skate boarding. The pool acts as an important aspect   overall design of the various components of the project......So carry on!  By the way these guys do parks all over the world.

skateboarders ruin my beautiful concrete

http://artofboard.com/

here's an idea...

from a step nephew of mine, i know that skating is bound by a near-universal vocabulary of moves (ollies, kickturns..etc). so, lets say, you organize the photoseries around each one of those moves. you make a stop motion presentation of each move (frame freeze). each of those moves entails an optimum (or optimally challenging) topograhy (stairs, ramps, ledges..etc). draw sections and plans of those architectural-landscape elements that falls under each of the sections. 

then, string the moves together to form one (fictional) skating journey - a choreography of your own making (or a skateboarder friend of yours).  in parallel, string up the corresponding plans and sections  to create an unravelled section and plan.

or somesing of that sort

It would be enlightening to compare regional and local architectural and social conditions to the style of skating that emerged. 

SoCal had a predominance of empty pools in suburban houses - a product of water and energy shortages, and the preference for Suburban post-war typologies in the west, which led to the emergence of pool skating, and by extension vert and bowl skating.

Philadelphia (and most of the east coast) on the other hand was a tightly packed urban environment with elements of urban decay and abandonment. No wonder then that street skating emerged from the East Coast.

Rodney Mullen learned to skate on a concrete pad in the middle of a cornfield in nebraska. If you look at it that way, it isn't surprising he has such mastery over tight technical tricks and nearly acrobatic skating. 

I could go on but I don't want to write your paper for you. tammuz' idea is also very good.

Another Video with a short write up in The Atlantic

Skateboarding, Space and the City: Architecture and the Body by Iain Borden is what you're looking for.

Try and show the relationship of how skateboarding adds to it evolves architecture or how architure evolves skating; Ie, new views on existing way or makes architects think outside the box like a skater. Or new architecture features push skateboarding to adapt. 

Try and make it so whatever the rest of your portfolio shows is similar enough so nothing sticks out like a sore thumb. Skaters becoming architects is also trending. (Maybe you could try focusing on one object(like block or ledge) highlight different uses by skaters and public. 
Main thing is have it make sense with the rest of the portfolio otherwise I would not include it so you don’t confuse viewers. Also look into the mainstream areas that skateboarding has started to take over. There are lots of crazy obstacles being built as more than just for skating. There’s skate houses designed by architects so it’s becoming more embraced as a medium to push architectural study