Hi, Ricky. I'm too lazy to change the colors on ALL of these corrections, so you are just going to have to wade through it and figure it out! Here goes:

Campus Party 2010

Hi, everybody.           (everyone is not a proper noun, so use a lower-case letter)

Today I'm going to talk about Campus Party 2010 (CP 2010).

CP 2010 is a technical event that takes place in Valencia every years.

Valencia is a big city on the east coast of Spain which is famous for being the natal land of "PAELLA". As well of PAELLA (??? not sure what you meant here --- maybe "in addition to'?), Valencia has a lot of interesting stuff to view.

One of the most important things is the architectural complex called "Ciudad de las Artes y las Ciencias" (traduced to english could be Sciences and Arts City). This complex was designed by the famous architect Santiago Calatrava. He has (using an apostrophe here doesn't work, even though it comes out that way in spoken language) designed, for example, the BCE Place in Toronto, among other things.

Anyway... CP is one of the biggest technical events in Europe. CP is divided in a group of areas: Free software, robotics, astronomy, simulation, Campus Blog, green campus, videogames and creativity.

The last one is my area and I am one of the contents coordinators. Our work consists of making the contents' schedule for the entire week. Also, we manage a couple of "in situ" projects that will be developed by the participants (called Campuseros) and our direction of them (??? you lost me on this last part).

Our area is divided in subareas too, such as: music, video, multimedia and graphic design, graphic programming and design tendencies...

This event is very, very interesting and funny. You leave the event with a lot of new knowledges and a new group of friends.

If you're interested in it, or you have something cool to show, don't hesitate to contact me.

I let you some links according with my explanation:  Can you rephrase this?
http://www.cac.es/
http://www.campus-party.es/2010/

You're welcome!